Thia-and/or selenafulvalenyl group-containing compound

ABSTRACT

A thia- and/or selenafulvalenyl group-containing compound of the formula (I), ##STR1## wherein each of X 1 , X 2 , X 3 , X 4 , X&#39; 1 , X&#39; 2 , X&#39; 3  and X&#39; 4  is independently S or Se, Y is an electron donating or electron accepting group having a size which is not so large as to prevent molecular overlapping, m is an integer of 0 to 4, each of Z 1 , Z 2 , Z&#39; 1  and Z&#39; 2  is independently a hydrogen atom, C n  H 2n+1  in which n is an integer of 1 to 5, or alternatively, a combination of Z 1  with Z 2  and Z&#39; 1  with Z&#39; 2  is C n  H 2n  in which n is an integer of 1 to 5, or X(C n  H 2n ) n&#39; , X in which X is S or Se and n&#39; is an integer of 1 to 3, and each of R 1 , R 2 , R 3 , R&#39; 1 , R&#39; 2  and R&#39; 3  is independently a hydrogen atom or C n  H 2n+1  in which n is an integer of 1 to 5. The compound has an electron donating nature and can be used to make electrically conductive complexes. The compound has an excellent thermal stability.

TECHNICAL FIELD

This invention relates to a novel thia- and/or selenafulvalenylgroup-containing compound and an electrically conductive complexcontaining this novel compound as an electron donor, and morespecifically to a novel thia- and/or selenafulvalenyl group-containingcompound having (i) the advantages of electron donating nature andcapability of giving an electrically conductive complex when only mixedwith an electron acceptor and (ii) the advantages of excellent thermalstability, etc., and an electrically conductive complex containing thisnovel compound as an electron donor.

TECHNICAL BACKGROUND

Although organic compounds have been generally considered to beinsulating materials, researches are being energetically conducted inorder to discover an organic compound having electrical conductivity. Asan organic electrically conductive compound, there is known acharge-transfer complex in which an electron donor and an electronacceptor are bonded to each other due to charge transfer between thesetwo members.

It is already known that complexes obtained by reacting a variety ofelectron acceptors with compounds having a thiafulvalene skeleton suchas tetrathiafulvalene (TTF), tetramethyltetrathiafulvalene (TMTTF),bisethylenedithiotetrathiafulvalene (BEDTTTF), etc., exhibit relativelygood electrical conductivity [a Japanese periodical "Kagaku Sosetsu",Vol. 42, page 59 (1983)].

However, among the above electron-donating compounds having athiafulvalene skeleton, TTF has the following defect: It is inferior inthermal stability due to its low melting point of 115° to 119° C. andcannot be applied to a part exposed to a high temperature, and the areafor its use is hence limited. TMTTF and BEDTTTF have excellent thermalstability over TTF, but have the following defect: these compounds haveno sufficient electron donating nature, and cannot form a complex whenonly directly mixed with a generally used electron acceptor, and it isrequired to employ a complicated method such as an electrolyticcrystallization method, or the like, in order to form a complex.

As described above, no organic compound has been found so far which hasgood electron donating nature, the capability of directly forming acomplex with an electron acceptor and excellent thermal stability.

Therefore, it is a first object of this invention to provide a novelorganic compound having good electron donating nature, the capability ofdirectly forming a complex with an electron acceptor and excellentthermal stability.

Further, it is a second object of this invention to provide anelectrically conductive complex containing, as an electron donor, anovel organic compound having good electron donating nature, thecapability of directly forming a complex with an electron acceptor andexcellent thermal stability.

DISCLOSURE OF THE INVENTION

The present inventors have made a diligent study to achieve the aboveobjects and as a result, found the following. (1) The organic compoundof the general formula (I), in which each of the two ends is terminatedwith a specific thia- and/or selenafulvalenyl group and each group isbonded with a specific aromatic divinyl group, has good electrondonating nature, the capability of directly forming a complex with anelectron acceptor and excellent thermal stability. And, (2) a complexcontaining the organic compound of the general formula (I) as anelectron donor, which is obtained by reacting this electron donor withan electron acceptor and has a specific molar ratio between the electrondonor and the electron acceptor, has electrical conductivity. Thisinvention has been completed on these findings.

That is, this invention has its gist in a thia- and/or selenafulvalenylgroup-containing compound of the general formula (I), ##STR2##

wherein:

each of X₁, X₂, X₃, X₄, X'₁, X'₂, X'₃ and X'₄ is independently S or Se,

Y is an electron donating or electron accepting substituent having asize which is not so large as to prevent molecular overlapping,

m is an integer of 0 to 4,

each of Z₁, Z₂, Z'₁ and Z'₂ is independently a hydrogen atom, C_(n)H_(2n+1) in which n is an integer of 1 to 5, or XC_(n) H_(2n+1) in whichX is S or Se and n is an integer of 1 to 5, or alternatively, acombination of Z₁ with Z₂ and that of Z'₁ with Z'₂ are C_(n) H_(2n) inwhich n is an integer of 1 to 5, or X(C_(n) H_(2n))_(n') X in which X isS or Se and n' is an integer of 1 to 3, and

each of R₁, R₂, R₃, R'₁, R'₂ and R'₃ is independently a hydrogen atom orC_(n) H_(2n+1) in which n is an integer of 1 to 5.

This invention also has its gist in an electrically conductive complexcontaining the thia- and/or selenafulvalenyl group-containing compoundof the general formula (I) as an electron donor, which is obtained byreacting this electron donor with an electron acceptor and has anelectron donor/electron acceptor molar ratio of 1/0.1 to 1/10.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an IR analysis chart of a compound of this invention, obtainedin Example 1.

FIG. 2 is an ¹ H-NMR analysis chart of a compound of this invention,obtained in Example 1.

FIG. 3 is a cyclic voltammetry chart of a compound of this invention,obtained in Example 1.

FIG. 4 is a mass spectrometry chart of a compound of this invention,obtained in Example 2.

FIGS. 5 and 6 are structural analysis charts obtained by X-raydiffraction of single crystals of a compound of this invention, obtainedin Example 2.

FIG. 7 is an ¹ H-NMR analysis chart of a compound of this invention,obtained in Example 5.

FIGS. 8 and 9 are structural analysis charts obtained by X-raydiffraction of single crystals of a compound of this invention, obtainedin Example 5.

FIG. 10 is an ¹ H-NMR analysis chart of a compound of this invention,obtained in Example 6.

FIG. 11 is an ¹ H-NMR analysis chart of a compound of this invention,obtained in Example 8.

FIG. 12 is an ¹ H-NMR analysis chart of a compound of this invention,obtained in Example 11.

FIG. 13 is an ¹ H-NMR analysis chart of a compound of this invention,obtained in Example 13.

FIG. 14 is an ¹ H-NMR analysis chart of a compound of this invention,obtained in Example 14.

FIG. 15 is an ¹ H-NMR analysis chart of a compound of this invention,obtained in Example 18.

FIG. 16 is an ¹ H-NMR analysis chart of an intermediate compound inExample 21.

FIG. 17 is an ¹ H-NMR analysis chart of a compound of this invention,obtained in Example 21.

PREFERRED EMBODIMENTS OF THE PRESENT INVENTION

As is clear in the above general formula (I), the novel thia- and/orselenafulvalenyl group-containing compound of this invention has thia-and/or selenafulvalenyl groups of the general formulae, one in oneterminal and the other in the other terminal. ##STR3## In the generalformulae (II) and (III), each of X₁, X₂, X₃, X₄, X'₁, X'₂, X'₃ and X'₄is independently S or Se. Therefore, specific examples of the generalformulae (II) and (III) are as follows, although the general formulaeshall not be limited thereto.

(Specific examples of the general formula (II)) ##STR4##

(Specific examples of the general formula (III)) ##STR5##

In the above example groups of the general formulae (II) and (III), eachof Z₁, Z₂, and Z₂ ' and Z₂ ' is independently a hydrogen atom, a loweralkyl group of the formula of C_(n) H_(2n+1) in which n is an integer of1 to 5, or a thio- or seleno-lower alkoxy group of the formula of XC_(n)H_(2n+1) in which X is S or Se and n is an integer of 1 to 5. The loweralkyl group of the formula of C_(n) H_(2n+1) is selected from methyl,ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl and tert-butyl groups,and the like. The thio- or seleno-lower alkoxy group of the formula ofXC_(n) H_(2n+1) is selected from thiomethoxy, selenomethoxy, thioethoxy,selenoethoxy, thio-n-propoxy, seleno-n-propoxy, thio-iso-propoxy,seleno-iso-propoxy, thio-n-butoxy, seleno-n-butoxy, thio-tert-butoxy,seleno-iso-butoxy, thio-tert-butoxy and seleno-tert-butoxy groups, andthe like.

In the above example groups of the formulae (II) and (III), Z₁ and Z₂may be bonded to each other, and Z₁ ' is and Z₂ ' may be bonded to eachother, to form an alkylene of the formula of C_(n) H_(2n) in which n isan integer of 1 to 5, or an alkylene group having sulfur and/or seleniumatoms in the terminals, represented by the formula of X(CH₂)_(n') X inwhich X is S or Se and n' is an integer of 1 to 5, such as adithioalkylene or a diselenoalkylene group. Typical examples of thealkylene group of the formula of C_(n) H_(2n) are methylene, ethylene,propylene and butylene groups, and typical examples of the alkylenegroup having sulfur and/or selenium atoms in the terminals, representedby the formula of X(CH₂)_(n') X, are S--CH₂ --S, Se--CH₂ --Se, S--(CH₂)₂--S, Se--(CH₂)₂ --Se, etc.

In the above example groups of the formulae (II) and (III), each of R₁and R₁ ' is independently a hydrogen atom or C_(n) H_(2n+1) in which nis an integer of 1 to 5. A lower alkyl group of C_(n) H_(2n+1) isselected from methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyland tert-butyl groups, and the like.

The compound of the general formula (I), provided by this invention, isa compound having the thia- and/or selenafulvalenyl groups of the abovegeneral formulae (II) and (III), one in its one terminal and the otherin the other terminal, and being formed by bonding these groups with anaromatic divinyl group of the general formula (IV). ##STR6## In thegeneral formula (IV), Y is an electron donating or electron acceptinggroup having a size which is not so large as to prevent molecularoverlapping. Typical examples of the electron donating group are loweralkyl groups having 1 to 5 carbon atoms such as methyl, ethyl, n-propyl,iso-propyl, n-butyl, iso-butyl, tert-butyl and other groups, loweralkoxy groups having 1 to 5 carbon atoms such as methoxy, ethoxy andother groups, thio-lower alkoxy groups having 1 to 5 carbon atoms suchas thiomethoxy, thioethoxy and other groups, an amino group, a hydroxylgroup, etc. Typical examples of the electron accepting group are halogenatoms such as chlorine, bromine, iodine, etc., a cyano group, a nitrogroup, etc.

In the formula (IV), each of R₂, R₃, R₂ ' and R₃ ' is independently ahydrogen atom or C_(n) H_(2n+1) in which n is an integer of 1 to 5.Typical examples of a lower alkyl group of the formula of C_(n) H_(2n+1)are methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert-butyland other groups.

The compound of the general formula (I), provided by this invention, canbe produced, e.g. by a known Wittig reaction. One preferred process forthe production thereof is as follows. In an ether-containing oralcohol-containing solvent, 1 mol of a formylthia and/orselenafulvalene-based compound such as formyltetrathiafulvalene,formyltetraselenafulvalene, or the like and 0.5 mol ofxylylenebis(triphenylphosphonium chloride) are reacted with each otherin the presence of 1 mol of a suitable base such as sodium ethoxide,n-butyllithium, t-butoxypotassium, or the like at a room temperature forseveral minutes to about 10 hours, whereby a desired compound can beobtained. When the reaction time is shorter than the above range, theyield is low. Even when the reaction is continued longer than the aboverange, the yield arrives at its peak, and no further improvement in theyield can be expected. In this reaction, the abovexylylenebis(triphenylphosphonium chloride) may be replaced withxylylenebis(triphenylphosphonium chloride) orxylylenebis(triphenylphosphonium bromide) having a substitutent of(Y)_(m) on the benzene ring, whereby a compound of the general formula(I) having (Y)_(m) as a substituent can be obtained.

Typical examples of the compound of the general formula (I) are asfollows.

Compound (Ia)

1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]benzene

Compound (Ib)

1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]-2,5-dimethylbenzene

Compound (Ic)

1,4-bis[2-(tetraselenafulvalen-2-yl)vinyl]-2,5-dimethylbenzene

Compound (Id)

1,4-bis[2-(3,6,7-trimethyltetraselenafulvalen-2-yl)vinyl]benzene

Compound (Ie)

1,4-bis[2-(6,7-ethylenedithiotetrathiafulvalen-2-yl)vinyl]-2,5-dimethylbenzene

Compound (If)

1,4-bis[2-(6,7-dimethylthiotetrathiafulvalen-2-yl)vinyl]-2,5-dimethylbenzene

Compound (Ig)

1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]-2-methoxybenzene

Compound (Ih)

1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]-2-chlorobenzene

Compound (Ii)

1,4-bis[2-(3,6,7-trimethyltetrathiafulvalen-2-yl)vinyl]benzene

Compound (Ij)

1-[2-(tetrathiafulvalen-2-yl)vinyl]-4-[2-(6,7-methylenedithiotetrathiafulvalen-2-yl)vinyl]-2,5-dimethylbenzene

Compound (Ik)

1-[2-(tetrathiafulvalen-2-yl)vinyl]-4-[2-(6,7-ethylenedithiotetrathiafulvalen-2-yl)vinyl]-2,5-dimethylbenzene

Compound (Il)

1-[2-(tetrathiafulvalen-2-yl)vinyl]-4-[2-(tetraselenafulvalen-2-yl)vinyl]-2,5-dimethylbenzene

Compound (Im)

1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]-2,5-dimethoxybenzene

Compound (In)

1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]-2,5-dichlorobenzene

Compound (Io)

1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]-2,3,5,6-tetramethylbenzene

Compound (Ip)

1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]-2-methyl benzene

Compound (Iq)

1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]-2,5-dihydroxybenzene

Compound (Ir)

1,4-bis[2-(1,4-dithia-5,8-diselenafulvalen-2-yl)vinyl]-2,5-dimethylbenzene

Compound (Is)

1,4-bis[2-(1,4-diselena-5,8-5,8-dithiafulvalen-2-yl)vinyl]-2,5-dimethylbenzene

Compound (It)

1,4-bis[2-(tetraselenafulvalen-2-yl)vinyl]-2,5-dichlorobenzene

Compound (Iu)

1,4-bis[2-(4,5,8-trithia-1-selenafulvalen-2-yl)vinyl]-2,5-dimethylbenzene

The compound of the general formula (I), provided by this invention, haselectron donating nature and can form an electrically conductive complexnot only by a general electrochemical method but also by only directlymixing it with an electron acceptor. The electron acceptor used forforming an electrically conductive complex may be any of organic andinorganic electron acceptors. The organic electron acceptor can beselected, for example, from 7,7,8,8-tetracyanoquinodimethane,2-methyl-7,7,8,8-tetracyanoquinodimethane,2,5-dimethyl-7,7,8,8-tetracyanoquinodimethane,2,5-diethyl-7,7,8,8-tetracyanoquinodimethane,2-methoxy-7,7,8,8-tetracyanoquinodimethane,2,5-dimethoxy-7,7,8,8-tetracyanoquinodimethane,2-methoxy-5-ethoxy-7,7,8,8-tetracyanoquinodimethane,2-methoxydihydrodioxabenzo-7,7,8,8-tetracyanoquinodimethane,2-chloro-7,7,8,8-tetracyanoquinodimethane,2-bromo-7,7,8,8-tetracyanoquinodimethane,2,5-dibromo-7,7,8,8-tetracyanoquinodimethane,2,5-diiodo-7,7,8,8-tetracyanoquinodimethane,2-chloro-5-methyl-7,7,8,8-tetracyanoquinodimethane,2-bromo-5-methyl-7,7,8,8-tetracyanoquinodimethane,2-iodo-5-methyl-7,7,8,8-tetracyanoquinodimethane,11,11,12,12-tetracyano-2,6-naphthoquinodimethane,1,1,2,3,4,4-hexacyanobutadiene,sodium-13,13,14,14-tetracyanodiphenoxydimethane, tetracyanoethylene,o-benzoquinone, p-benzoquinone, 2,6-naphthoquinone, diphenoquinone,tetracyanodiquinone, p-fluoranil, tetrachlorodiphenoquinone, etc. Theinorganic electron accpetor is selected, for example, from halogenelements such as iodine, bromine, chlorine, etc., trihalide anions suchas I₃, I₂ Br, IBr₂, Br₃, Cl₃, etc., SCN, Cu(SCN)₂, pseudohalogenmolecules such as AuI₂, AuBr₂, AuCl₂, etc. and electron acceptingmolecules such as ClO₄, PF₆, BF₄, etc.

In this charge-transfer complex, the molar ratio (D/A) of the electrondonor (the compound of the general formula (I) provided by thisinvention) to the electron acceptor is 1/0.1 to 1/10. The reasontherefor is as follows. When the D/A exceeds 1/0.1, the electricalconductivity is decreased, and when the D/A is less than 1/10, adecrease in the electrical conductivity is similarly observed. Theso-obtained complex has electrical conductivity and can be used as anorganic electrically conductive material.

The compound of the general formula (I), provided by this invention, hasexcellent thermal stability over existing tetrathiafulvalene (TTF), andtherefore can expand the fields and areas where this compound and acomplex obtained by a reaction between this compound and an electronacceptor are used. For example, a complex containing the compound of thegeneral formula (I), provided by this invention, as an electron donorcan be applied to an automobile-use printed circuit board exposed to ahigh temperature.

This invention will be explained further in detail hereinafter.

Preparation of compound of general formula (I) provided by thisinvention Example 1 Preparation of1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]benzene [Compound (Ia)]

2.18 Grams (3.1 mmol) of p-xylylenebis(triphenylphosphonium chloride)was suspended in 15 ml of THF, and 5 ml of a hexane solution ofn-butyllithium (concentration 14% by weight) was added to the resultantsuspension under argon gas current. Thereafter, a solution containing1.43 g (6.16 mmol) of 2-formyltetrathiafulvalene and 10 ml of THF wasadded dropwise, and the resultant mixture was allowed to react at roomtemperature for 6 hours with stirring. Then, 50 ml of methanol was addedto terminate the reaction, and the reaction mixture was filtered toobtain a reaction product. The reaction product was consecutively washedwith methanol, washed with water, washed with methanol, recrystallizedfrom dimethylformamide (to be referred to as DMF hereinafter), and thendried to give 0.60 g of a reddish brown solid (yield 36%). The reddishbrown solid obtained in this Example 1, i.e. Compound (Ia), had athermal decomposition temperature, Td, of 225° C. (The thermaldecomposition temperature was defined as a temperature at which theweight decreased by 5% by weight according to TG (thermogravimetricanalysis)), and was found to be excellent in thermal stability.Elemental analysis thereof showed the following.

    ______________________________________                                                   C          H     S                                                 ______________________________________                                        Calculated (%)                                                                             49.4         2.6   47.9                                          Found (%)    49.5         2.7   47.8                                          ______________________________________                                    

Mass spectrometric analysis of Compound (Ia) showed M/Z of 534. Further,Compound (Ia) was structurally analyzed by IR measurement and ¹ H-NMR(400 MHz) measurement. The IR analysis chart is shown in FIG. 1, and the¹ H-NMR analysis chart is shown in FIG. 2. In the IR analysis chart inFIG. 1, absorption based on the exterior of the C-H plane of a vinylgroup was clearly observed at 943 cm⁻¹, whereby the presence of vinylbonds was recognized.

The results of assignment of the ¹ H-NMR analysis chart in FIG. 2 are asfollows.

    ______________________________________                                        Peak No. ppm       Assignment                                                                              Integration ratio                                ______________________________________                                        1        8.45      a         1                                                2        6.52      a         1                                                3        6.82      b         4                                                4        7.0       c         2                                                5        7.3       d         1                                                6        7.35      d         1                                                7        7.6       e         4                                                ______________________________________                                    

The above analysis results showed that Compound (Ia) obtained in thisExample was 1,4-bis[2-tetrathiafulvalen-2-yl)vinyl]benzene of thefollowing formula. ##STR7##

Compound (Ia) obtained in this Example 1 was measured for a firstoxidation potential (E₁) and a second oxidation potential (E₂) by acyclic voltammetry. The measurement conditions were as follows.

    ______________________________________                                        Reference electrode    Ag/AgCl                                                Supporting electrolyte n-Bu.sub.4 NBF.sub.4                                   Solvent                Chlorobenzene                                          Electrolyte concentration                                                                            100 mmol/l                                             Sample compound concentration                                                                        0.5 mmol/l                                             ______________________________________                                    

FIG. 3 shows the results of the cyclic voltammetry. A current-voltagecurve is drawn with the ordinate axis as current and the abscissa axisas voltage. In this case, a peak appears due to a sharp increase incurrent when the voltage is increased to a voltage at which a samplecompound releases an electron. As is clearly shown in FIG. 4, thecompound (Ia) of this Example 1 shows four peaks p₁, p₂, p₃ and p₄ sinceit releases four electrons one by one. And, a value obtained bysubtracting 0.03 V from the voltage at the peak p₁ when a first electronis released is referred to as a first oxidation potential E₁, and thevoltage at the peak p₂ is referred to as a second potential E₂.

It is known that a sample compound having a lower E₁ value is richer inelectron donating nature. In Compound (Ia) of this Example 1, the E₁value was 0.49 V as is clear in FIG. 3, and this value was lower thanthe E₁ value (1.0 V) of bisethyleneditetrathiafulvalene (BEDTTTF), theE₁ value (0.86 V) of tetramethyltetrathiafulvalene (TMTTF) and the E₁value (0.85 V) of tetrathiafulvalene (TTF) shown in Comparative Example1 which will be described later (see Table 1).

According to literature, a compound having a smaller difference (ΔE)between the second oxidation potential E₂ and the first oxidationpotential E₁ is generally a higher electron donor (see e.g. A. F.Gariito et al, Acc. Chem. Res., 7, 232 (1974); Z. Yoshida et al,Tetrahedron Lett., 24, 3473 (1983), M. R. Bryce, Tetrahedron Lett., 25,2403 (1984). In Compound (Ia) of this Example 1, as is clear in FIG. 3,ΔE was 0.31 V, and this value is smaller than the ΔE (0.44 V) ofBEDTTTF, the ΔE (0.53 V) of TMTTF and the ΔE (0.41 V) of TTF shown inComparative Example 1 (see Table 1).

It is, therefore, clearly shown that Compound (Ia) of this Example 1 isricher in electron donating nature than the three known compounds inComparative Example 1 since it has a lower E₁ and a smaller ΔE thanthese compounds.

Further, as is clear in Example 22 which will be described later, it wasfound that the compound (Ia) of this Example 1 was capable of forming acomplex with an electron acceptor under a direct complex forming method.

Example 2 Preparation of1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]-2,5-dimethylbezene [Compound(Ib)]

5 Grams (24.5 mmol) of 2,5-bis(chloromethyl)-p-xylene and 27 g (4equivalent weight) of triphenylphosphine were added to 100 ml of DMF,and the resultant mixture was heated in an oil bath (bath temperatureabout 130° C.). After 50 minutes, while the reaction mixture was hot, itwas filtered to obtain a reaction product, and the reaction product waswashed with acetone, and dried to give 16.5 g of2,5-dimethyl-p-xylylenebis(triphenylphosphonium chloride) (yield 92.6%).

Then, 2 g (2.75 mmol) of the above-obtained compound was suspended in 30ml of THF. Then, under an argon gas current, 3.5 ml of a hexane solutionof n-butyllithium (concentration 14% by weight) was added dropwise tothe resultant suspension over 5 minutes. Further, a solution containing1.28 g (5.50 mmol) of 2-formyltetrathiafulvalene and 10 ml of THF wasadded dropwise, and the resultant mixture was allowed to react at roomtemperature for 6 hours with stirring. Thereafter, 3 ml of methanol wasadded to terminate the reaction, the solvent was distilled off, and theresultant product was washed with water, washed with methanol,recrystallized from DMF, filtered and dried to give 1.16 g of a brownsolid (yield 68%). The brown solid obtained in this Example 2, i.e.Compound (Ib) had a decomposition temperature Td of 270° C. or was foundto be excellent in thermal stability. Elemental analysis values thereofare as follows.

    ______________________________________                                                   C          H     S                                                 ______________________________________                                        Calculated (%)                                                                             51.2         3.2   45.6                                          Found (%)    51.4         3.3   45.3                                          ______________________________________                                    

FIG. 4 shows the mass spectrometry chart of Compound (Ib) obtained inthis Example 2. As is clear in FIG. 4, Compound (Ib) had M/Z of 562.

The above results showed that Compound (Ib) was1,4-bis[2-tetrathiafulvalen-2-yl)vinyl]-2,5-dimethylbenzene of thefollowing formula. ##STR8##

Compound (Ib) of this Example 2 was measured for E₁ and ΔE in the samemanner as in the case of Compound (Ia) of Example 1 to show E₁ of 0.47 Vand ΔE of 0.23, or found to be as rich in electron donating nature asCompound (Ia) of Example 1. As is clear in Example 22 which will bedescribed later, it was also found that Compound (Ib) of this Example 1was capable, similarly to Compound (Ia) of Example 1, of forming acomplex with an electron acceptor under a direct complex forming method.

FIGS. 5 and 6 show structure analysis charts based on four-axis X-raydiffraction of single crystals of Compound (Ib) of this Example 2,measured by means of a four-axis X-ray diffractometer AFC-5R supplied byRigaku Denki K.K.

On the basis of FIG. 5, the results of crystal structure analysis ofthis compound were as follows.

The compound had an R value of 0.053, and it was a single crystal havinglattice parameters in which a=7.770 Å, b=34.949 Å, c=9.314 Å, β=91.972°,and V=2,528 Å³, and a space group P2_(1/c) (#14). The chemical formulanumber Z in a unit lattice was 4. In addition, FIG. 6 shows an enlargedview of only one molecule of the compound.

Example 3 Preparation of1,4-bis[2-(tetraselenafulvalen-2-yl)vinyl]-2,5-dimethylbenzene [Compound(Ic)]

1.96 Grams (5 mmol) of tetraselenafulvalene was dissolved in 100 ml oftetrahydrofuran, and the resultant mixture was cooled to -65° C. Underan argon gas current, 20 ml of tetrahydrofuran solution of 0.535 g (5mmol) of LDA (lithium diisopropylamide) was added dropwise over about 30minutes, and the resultant mixture was stirred for further 30 minutes.Thereafter, a solution formed was passed through a Teflon tube underargon pressure, and added to a mixture solution (-70° C.) consisting of50 mmol of DMF and 100 ml of tetrahydrofuran. Then, the resultantmixture was brought back to room temperature, and subjected, after waterwas added, to extraction with ether. The ether was evaporated, and theresidue was purified by column chromatography to give 0.9 g (2.1 mmol)of 2-formyltetraselenafulvalene (melting point 127.4° C.).

On the other hand, 0.75 g (1.1 mmol) ofp-xylylenebis(triphenylphosphonium chloride) was suspended in 15 ml ofTHF, and under argon gas current, 5 ml of a hexane solution ofn-butyllithium (concentration 14%) was added dropwise, and then, asolution of 0.9 g (2.1 mmol) of the 2-formyltetraselenafulvalene in 10ml of THF was added dropwise to the reaction solution. The resultantreaction solution was allowed to react by stirring it at roomtemperature for 6 hours. Thereafter, 50 ml of methanol was addeddropwise to terminate the reaction, and the reaction solution wasfiltered. And, the resultant product was consecutively washed withmethanol, with water, and with methanol, and dried to give 0.4 g of theintended Compound (Ic) (yield 39%).

Table 1 summarizes the thermal decomposition temperature Td of Compound(Ic), its elemental analysis values, its M/Z in mass spectrometry, itsE₁ and ΔE determined by cyclic voltammetry, and its capability ofdirectly forming a complex. As is clear in Table 1, Compound (Ic) had athermal decomposition temperature Td of as high as 230° C., or was foundto be excellent in thermal stability. Further, the elemental analysisvalues and M/Z in mass spectrometry showed that Compound (Ic) was1,4-bis[2-(tetraselenafulvalen-2-yl)vinyl]-2,5-dimethylbenzene of thefollowing formula. ##STR9##

Compound (Ic) had E₁ of 0.57 V and ΔE of 0.2 V, or found to be rich inelectron donating nature. As is detailed in Example 22 which will bedescribed later, it was also found that Compound (Ic) was also capableof forming a complex with an electron acceptor under a direct complexforming method.

Example 4 Preparation of1,4-bis[2-(3,6,7-trimethyltetraselenafulvalen-2-yl)vinyl]benzene[Compound (Id)]

2 Grams (4.6 mmol) of tetramethylselenafulvalene was dissolved in 200 mlof anhydrous carbon tetrachloride, and 2 g of NBS (N-bromosuccinimide)and 0.3 g of benzoyl peroxide were added. The resultant mixture wasgradually heated in an oil bath with stirring vigorously. The reactionwas exothermic, and proceeded with releasing heat. After the heatrelease terminated, the reaction mixture was stirred further for 1 hour.

After the reaction mixture was cooled and filtered, the carbontetrachloride was evaporated, and the residue was distilled underreduced pressure. Added to the distillate was 20 ml (161 mmol) oftriethyl phosphite, and the resultant mixture was heated at 120° C. for5 hours. The reaction mixture was filtered, followed by washing withdichloromethane and separation with a column, whereby a monoreactantalone was separated and recovered. This monoreactant was reacted withterephthalaldehyde according to an ordinary Wittig reaction (n-BuLi/THFsystem) to give 0.05 g of the intended Compound (Id) (yield 2%).

Table 1 summarizes the thermal decomposition temperature Td of Compound(Id), its elemental analysis values, its M/Z in mass spectrometry, itsE₁ and ΔE determined by cyclic voltammetry, and its capability ofdirectly forming a complex. As is clear in Table 1, Compound (Id) had athermal decomposition temperature Td of as high as 245° C., or was foundto be excellent in thermal stability. Further, the elemental analysisvalues and M/Z in mass spectrometry showed that Compound (Id) was1,4-bis[2-(3,6,7-trimethyltetraselenafulvalen-2-yl)vinyl]-2,5-dimethylbenzeneof the following formula. ##STR10##

Compound (Id) had E₁ of 0.53 V and ΔE of 0.3 V, or found to be rich inelectron donating nature. As is detailed in Example 22 which will bedescribed later, it was also found that Compound (Id) was also capableof forming a complex with an electron acceptor under a direct complexforming method.

Example 5 Preparation of1,4-bis[2-(6,7-ethylenedithiotetrathiafulvalen-2-yl)vinyl]-2,5-dimethylbenzene[Compound (Ie)]

30 Grams (0.12 mol) of dimethyl 1,3-dithiol-2-thion-4,5-dicarboxylatesynthesized according to the method of G. C. Papavassiliou, et al[Synthetic Metals, Vol. 27 (1988) B-373-B378] was dissolved in 30 ml ofhexamethylphosphorictriamide (HMPA), and 12.6 g (0.12 mol) of lithiumbromide monohydrate was added. The resultant mixture was heated at 60°C. for 1 hour, the reaction mixture was allowed to cool to roomtemperature, 200 ml of water was added, and a yellow solid formed wasseparated by filtering and washed with water. The solid obtained wasdried and recrystallized from carbon tetrachloride to give 16.2 g ofyellow acicular crystals of methyl 1,3-dithiol-2-thione-4-carboxylate(yield 70%).

2.3 Grams (11.2 mmol) of 4,5-ethylenedithio-1,3-dithiol-2-one and 4.3 g(22.4 mmol) of methyl 1,3-dithiol-2-thion-4-carboxylate were dissolvedin 30 ml of toluene, and 10 ml (60 mmol) of triethyl phosphite wasadded. The resultant mixture was refluxed in an argon gas current for 2hours. Acicular crystals (2,3,6,7-bisethylenedithiotetra-thiafulvalene,0.8 g) formed when the reaction mixture was allowed to cool to roomtemperature was removed by filtering, and the filtrate was concentratedand distilled under reduced pressure to remove P(OEt)₃. The remainingblack solid was purified with column chromatography to give 0.8 g of ared solid of 2,3-ethylenedithio-6-methoxycarbonyltetrathiafulvalene(yield 20%).

4.9 Grams of a 70% toluene solution of sodiumbis(2-methoxyethoxy)aluminum hydride (SMEAH) (containing 17.1 mmol ofSMEAH) was dissolved in 6 ml of anhydrous toluene, and the resultantmixture was cooled to 0° C. under an argon gas current. A solution of1.6 g (18.4 mmol) of anhydrous morpholin (MPL) in anhydrous toluene wasslowly added dropwise to the mixture over 30 minutes to prepare anSMEAH-MPL mixed reagent.

2 Grams (5.7 mmol) of2,3-ethylenedithio-6-methoxycarbonyltetrathiafulvalene was dissolved in120 ml of anhydrous toluene, and the resultant mixture was cooled to 0°C. The above SMEAH-MPL mixed reagent was slowly added dropwise to themixture over 30 minutes under an argon gas current. After the addition,the mixture was stirred at 0° C. for 30 minutes, and while the mixturehad a temperature of 0° C., 2N sulfuric acid was added to acidify themixture solution. Anhydrous magnesium sulfate was added to solidify awater phase, and the solution was filtered. The remaining solid waswashed with dichloromethane, and these two liquids (filtrate anddichloromethane wash liquid) were together concentrated and purified bycolumn chromatography to give 0.46 g of a red solid of6,7-ethylenedithio-2-formyltetrathiafulvalene (m.p. 153° C., yield 25%).

0.28 Gram (0.369 mmol) of 2,5-dimethylxylylenebistriphenylphosphoniumwas suspended in 20 ml of anhydrous THF, and at room temperature andunder an argon gas current, 1.0 ml of a hexane solution of 15%n-butyllithium (containing 1.6 mmol of n-butyllithium) was added. Afterthe resultant mixture was stirred at room temperature for 5 minutes, asolution of 0.25 g (0.78 mmol) of6,7-ethylenedithio-2-formyltetrathiafulvalene in 20 ml of an anhydrousTHF was added to the mixture, and the mixture was stirred at roomtemperature for 2 hours. An equivalent amount of methanol was added toterminate the reaction, and a solid formed was separated by filtering,and washed with methanol. The solid was recrystallized from DMF to give80 mg of golden plate-like crystals of the intended Compound (Ie) (yield28%).

Table 1 summarizes the thermal decomposition temperature Td of Compound(Ie), its elemental analysis values, its M/Z in mass spectrometry, itsE₁ and ΔE determined by cyclic voltammetry, and its capability ofdirectly forming a complex. As is clear in Table 1, Compound (Ie) had athermal decomposition temperature Td of as high as 227° C., or was foundto be excellent in thermal stability.

Further, the elemental analysis values, the M/Z in mass spectrometry and¹ H-NMR shown in FIG. 7 showed that Compound (Ie) was1,4-bis[2-(6,7-ethylenedithiotetrathiafulvalen-2-yl)vinyl]-2,5-dimethylbenzeneof the following formula. ##STR11##

Compound (Ie) had E₁ of 0.55 V and ΔE of 0.26 V, or found to be rich inelectron donating nature. As is detailed in Example 22 which will bedescribed later, it was also found that Compound (Ie) was also capableof forming a complex with an electron acceptor under a direct complexforming method.

FIGS. 8 and 9 are structural analysis charts obtained by X-raydiffraction of single crystals of Compound (Ie) obtained in this Example5. On the basis of FIG. 8, the structural analysis of this Compound (Ie)are as follows.

Compound (Ie) had an R value of 0.071, and it was a single crystalhaving lattice parameters in which a=8.287 Å, b=13.803 Å, c=27.54 Å,β=92.94°, and V=3,146 Å³ and a space group P2_(1/c) (#14). The chemicalformula number Z in a unit lattice was 4. In addition, FIG. 9 shows anenlarged view of only one molecule of this Compound.

Example 6 Preparation of1,4-bis[2-(6,7-bismethylthiotetrathiafulvalen-2-yl)vinyl]-2,5-dimethylbenzeneCompound (If)

Dimethyltetrathiafulvalene 2,3-bismethylthio-6,7-dicarboxylate wassynthesized according to the method of G. C. Papavassiliou, et al[Synthetic Metals, Vol. 27 (1988) B373-B378].

That is, 5.75 g (27.4 mmol) of 4,5-dimethylthio-1,3-dithiol-2-one and13.7 g (54.8 mmol) of methyl 1,3-dithiol-2-thion-4-carboxylate weredissolved in 120 ml of toluene, and 60 ml (360 mmol) of triethylphosphite was added. The resultant mixture was refluxed in an argon gascurrent for 7 hours. The reaction mixture was allowed to cool to roomtemperature, and the filtrate was concentrated and distilled underreduced pressure to remove triethyl phosphite. Added to the remainingsolid was 100 ml of methanol, and the resultant mixture was filtered.The filtrate was purified by column chromatography to give 1.32 g (3.2mmol) of a dense reddish brown solid of diemthyltetrathiafulvalene2,3-dimethylthio-6,7-dicarboxylate (yield 11.7%).

Then, 1.32 Grams (3.2 mmol) of dimethyltetrathiafulvalene2,3-bismethylthio-6,7-dicarboxylate was dissolved in 50 ml ofhexamethylphosphoricamide (HMPA), and 2.15 g (24.8 mmol) of lithiumbromide monohydrate was added. The resultant mixture was heated at 150°C. for 15 minutes. The reaction mixture was allowed to cool to roomtemperature, 400 ml of water was added, and the resultant mixture wassubjected to extraction with dichloromethane. The extract was drid overmagnesium sulfate and subjected to evaporation. Further, the residue washeated in an oil bath at 100° C., HMPA was distilled off under reducedpressure, and dichloromethane was added. The resultant mixture waspurified by a silica column to give 0.546 g (1.84 mmol) of of2,3-dimethylthiotetrathiafulvalene (yield 57.5%). Added to the entireamount thereof were 0.257 g (2.21 mmol) of ethylenediamine and 40 ml ofether. And, the resultant mixture was cooled to -78° C. with dryice-ethanol, and 1.26 ml of a hexane solution of 15% n-butyllithium(containing 2.02 mmol of n-butyllithium) was added thereto dropwise over10 minutes. The mixture was further stirred for 1 hour, and 1.4 ml (18.4mmol) of DMF and 40 ml of ether which were cooled to -78° C. were forcedinto the mixture under argon pressure through a Teflon tube. Then, thedry ice bath was removed to bring the resultant suspension back to roomtemperature. The suspension was poured into 250 ml of pure water, andthe mixture was subjected to extraction with ether, followed by dryingwith magnesium sulfate and purification by column chromatography,whereby there was obtained 0.26 g (0.8 mmol) of2,3-bismethylthio-6-formyltetrathiafulvalene (yield 43.5%).

0.29 Gram (0.4 mmol) of 2,5-dimethylxylylenebistriphenylphosphoniumchloride was suspended in 20 ml of anhydrous THF, and 1.0 ml of a hexanesolution of 15% n-butyllithium (containing 1.6 mmol of n-butyllithium)was added at room temperature under an argon gas current. After theresultant mixture was stirred at room temperature for 5 minutes, asolution of 0.26 g (0.8 mmol) of2,3-bismethylthio-6-formyltetrathiafulvalene in 20 ml of anhydrous THFwas added, and the mixture was stirred at room temperature for 2 hours.An equal amount of methanol was added to terminate the reaction, and theresultant solid was separated by filtering and washed with methanol togive 90 mg of the intended Compound (If) (yield 30%).

Table 1 summarizes the thermal decomposition temperature Td of Compound(If), its elemental analysis values, its M/Z in mass spectrometry, itsE₁ and ΔE determined by cyclic voltammetry, and its capability ofdirectly forming a complex. As is clear in Table 1, Compound (If) had athermal decomposition temperature of as high as 236° C., or was found tobe excellent in thermal stability.

Further, the elemental analysis values, the M/Z in mass spectrometry and¹ H-NMR shown in FIG. 10 showed that Compound (If) was1,4-bis[2-(6,7-bismethylthiotetrathiafulvalen-2-yl)vinyl]-2,5-dimethylbenzeneof the following formula. ##STR12##

Compound (If) had E₁ of 0.52 V and ΔE of 0.32 V, or found to be rich inelectron donating nature. As is detailed in Example 22 which will bedescribed later, it was also found that Compound (If) was also capableof forming a complex with an electron acceptor under a direct complexforming method.

Example 7 Preparation of1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]-2-methoxybenzene [Compound(Ig)]

1,4-Dibromomethyl-2-methoxybenzene was synthesized according to themethod of Marcel Hibert, et al [J. Org. Chem. 45, 4,496-4,498 (1980)].Added thereto was triphenylphosphine, and the resultant mixture washeated in DMF. Bis-1,4-(triphenylphosphoniumbromo)-2-methoxybenzeneprecipitated was separated by filtering, dried and used in the followingreaction. That is, 1.0 g (1.2 mmol) of thisbis-1,4-(triphenylphosphoniumbromo)-2-methoxybenzene was suspended in 15ml of THF, and under an argon current, 5 ml of a hexane solution ofn-butyllithium (concentration 14%) was added dropwise. Added dropwise tothe resultant mixture was a solution of 0.6 g (2.6 mmol) of2-formyltetrathiafulvalene in 10 ml of THF, and the mixture was stirredat room temperature for 6 hours. Then, 50 ml of methanol was addeddropwise to terminate the reaction, followed by filtering, washing withmethanol, washing with water, washing with methanol, recrystallizationfrom DMF and drying, whereby 0.3 g of the intended Compound (Ig) wasobtained (yield 41%).

Table 1 summarizes the thermal decomposition temperature Td of Compound(Ig), its elemental analysis values, its M/Z in mass spectrometry, itsE₁ and ΔE determined by cyclic voltammetry, and its capability ofdirectly forming a complex. As is clear in Table 1, Compound (Ig) had athermal decomposition temperature Td of as high as 220° C., or was foundto be excellent in thermal stability. Further, the elemental analysisvalues and the M/Z in mass spectrometry showed that Compound (Ig) was1,4-bis[2-tetrathiafulvalen-2-yl)vinyl]-2-methoxybenzene of thefollowing formula. ##STR13##

Compound (Ig) had E₁ of 0.46 V and ΔE of 0.31 V, or found to be rich inelectron donating nature. As is detailed in Example 22 which will bedescribed later, it was also found that Compound (Ig) was also capableof forming a complex with an electron acceptor under a direct complexforming method.

Example 8 Preparation of1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]-2-chlorobenzene [Compound (Ih)]

A 200 ml round-bottomed flask was charged with 7.0 g (50 mmol) of2-chloro-p-xylene and 22.8 g (0.13 mol) of N-bromosuccinimide, andfurther charged with 100 ml of carbon tetrachloride. 1 Gram (4 mmol) ofbenzoyl peroxide was added, and the resultant mixture was graduallyheated in an oil bath which was preliminarily heated to 90° C. Whenabout five minutes passed, the mixture started a reaction, and themixture was heat-refluxed for 80 minutes. The reaction mixture wasallowed to cool, and the carbon tetrachloride was distilled off with arotary evaporator. Added to the residue were 100 ml of THF and 30 g (114mmol) of triphenylphosphine, and the mixture was heat-refluxed for 3hours. A solid precipitated was separated, washed with a small amount ofTHF, and recrystallized from methanol to give 8.6 g (11 mmol) of thephosphonium salt (yield 22%). A 100 ml flask was subjected toreplacement with argon, and charged with 1.6 g (1.9 mmol) of the abovephosphonium salt and 10 ml of anhydrous THF. When a solution of 0.4 g(3.6 mmol) of potassium tert-butoxide in 10 ml of anhydrous THF wasadded dropwise with stirring, the resultant mixture was colored in darkreddish brown as a whole. This mixture was stirred at room temperaturefor 15 minutes, and a solution of 1 g (4.3 mmol) of2-formyltetrathiafulvalene in 10 ml of anhydrous THF was added dropwise.The resultant mixture was stirred for 30 minutes, and then, a smallamount of methanol and water was added to allow an excess amount ofalkali to react, followed by washing with a large amount of methanol andfiltering. 100 Milliliters of dichloromethane was added, and the mixturewas filtered and subjected to a silica column. Then, the solvent wasdried and distilled off to give 0.18 g of the intended Compound (Ih)(yield 17%).

Table 1 summarizes the thermal decomposition temperature Td of Compound(Ih), its elementatl analysis values, its M/Z in mass spectrometry, itsE₁ and ΔE determined by cyclic voltammetry, and its capability ofdirectly forming a complex. As is clear in Table 1, Compound (Ih) had athermal decomposition temperature of as high as 248° C., or was found tobe excellent in thermal stability.

Further, the elemental analysis values, the M/Z in mass spectrometry and¹ H-NMR shown in FIG. 11 showed that Compound (Ih) was1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]-2-chlorobenzene of thefollowing formula. ##STR14##

Compound (Ih) had E₁ of 0.49 V and ΔE of 0.31 V, or found to be rich inelectron donating nature. As is detailed in Example 22 which will bedescribed later, it was also found that Compound (Ih) was also capableof forming a complex with an electron acceptor under a direct complexforming method.

Example 9 Preparation of1,4-bis[2-(3,6,7-trimethyltetrathiafulvalen-2-yl)vinyl]benzene [Compound(Ii)

5 Grams (19 mmol) of tetramethyltetrathiafulvalene was dissolved in 20ml of anhydrous carbon tetrachloride, and 3.4 g of NBS(N-bromosuccinimide) and 0.5 g of benzoyl peroxide were added. Theresultant mixture was heated in an oil bath with stirring vigorously.The reaction proceeded with generating heat. After the heat generationstopped, the reaction mixture was further stirred for 1 hour. Thereaction mixture was cooled and filtered, and the carbon tetrachloridewas evaporated. The residue was distilled under reduced pressure. Addedto the resultant distillate was 50 ml (403 mmol) of triethylphosphite,and the resultant mixture was heated at 120° C. for 5 hours. Thereaction liquid was filtered, followed by washing with dichloromethaneand separation with a column, whereby a monoreactant alone wasrecovered. This monoreactant and terephthalaldehyde were reacted witheach other according to a conventional Wittig reaction (n-BuLi/THFsystem) to give 0.2 g of the intended Compound (Ii) (yield 3%).

Table 1 summarizes the thermal decomposition temperature Td of Compound(Ii), its elemental analysis values, its M/Z in mass spectrometry, itsE₁ and ΔE determined by cyclic voltammetry, and its capability ofdirectly forming a complex. As is clear in Table 1, Compound (Ii) had athermal decomposition temperature Td of as high as 270° C., or was foundto be excellent in thermal stability. Further, the elemental analysisvalues and the M/Z in mass spectrometry showed that Compound (Ii) was1,4-bis[2-(3,6,7-trimethyltetrathiafulvalen-2-yl)vinyl]benzene of thefollowing formula. ##STR15##

Compound (Ii) had E₁ of 0.48 V and ΔE of 0.32 V, or found to be rich inelectron donating nature. As is detailed in Example 22 which will bedescribed later, it was also found that Compound (Ii) was also capableof forming a complex with an electron acceptor under a direct complexforming method.

Example 10 Preparation of1-[2-(tetrathiafulvalen-2-yl)-vinyl]-4-[2-(6,7-methylenedithiotetrathiafulvalen-2-yl)vinyl]-2,5-dimethylbenzene[Compound (Ij)]

A 500 ml three-necked round-bottomed flask was charged with 0.3 g (1.3mmol) of 2-formyltetrathiafulvalene and 0.94 g (1.3 mmol) of2,5-dimethylxylylenebistriphenylphosphonium chloride, and under an argonatmosphere, 200 ml of anhydrous 2-propanol was added. While theresultant mixture was heated in a hot water bath, it was stirred with amechanical stirrer until a solution was formed. The solution was allowedto cool, and while the solution was vigorously stirred, a 2-propanolsolution of lithium 2-propoxide [prepared by adding 0.8 ml ofn-butyllithiumhexane solution (containing 1.3 mmol of n-butyllithium)dropwise to 100 ml of 2-propanol] was added dropwise with a droppingfunnel over 2 hours. Thereafter, the resultant mixture was stirred atroom temperature for 2 hours. The reaction liquid became reddish orangeto form a precipitate. The reaction mixture was subjected to suctionfiltration, and the filtrate was concentrated to about 10 ml bydistilling off the solvent with a rotary evaporator. The filtrate wasallowed to stand to precipitate a solid by crystallization, and thesolid was separated by filtering, washed with a small amount of2-propanol, and dried under vacuum to give 480 mg (0.74 mmol) of[2,5-dimethyl-4-(2-tetrathiafulvalenylethenyl)]benzyltriphenylphosphoniumchloride (yield 57%).

Then, 2,3-methylenedithio-6,7-dimethoxycarbonyltetrathiafulvalene wassynthesized according to the method of G. C. Papavassiliou, et al[Synthetic Metals, Vol. 27 (1988) B373-B378].

That is, 3.9 g (20.0 mmol) of 4,5-methylenedithio-1,3-dithiol-2-one and10 g (40 mmol) of dimethyl 1,3-dithiol-2-thion-4,5-dicarboxylate weredissolved in 80 ml of toluene, and 40 ml (240 mmol) of triethylphosphite was added. The resultant mixture was refluxed in an argon gascurrent for 2 hours. The reaction mixture was allowed to cool to roomtemperature, concentrated and distilled under reduced pressure to removetriethyl phosphite. Added to the remaining liquid was 100 ml of methanolto precipitate a solid, and the solid was separated by filtering, andpurified by column was separated by filtering, and purified by columnchromatography to give 2.7 g of a red solid of2,3-methylenedithio-6,7-dimethoxycarbonyltetrathiafulvalene (yield 34%).

Then, 2.7 g (6.7 mmol) of the so-obtained2,3-methylenedithio-6,7-dimethoxycarbonyltetrathiafulvalene wasdissolved in 30 ml of hexamethylphosphoricamide (HMPA), 1.1 g (10 mmol)of lithium bromide monohydrate was added, and the resultant mixture washeated at 80° C. for 30 minutes. The reaction mixture was allowed tocool to room temperature, 100 ml of methanol was added, and a red solidformed was separated by filtering and washed with methanol. The redsolid was dried to give 2.1 g of a red crystal of2,3-methylenedithio-6-methoxycarbonyltetrathiafulvalene (melting point190° C., yield 93%). 4.9 Grams (17.1 mmol) of a toluene solution of 70%sodium bis(2-methoxyethoxy)-aluminum hydroxide (SMEAH) was dissolved in6 ml of anhydrous toluene, and the resultant mixture was cooled to 0° C.under an argon gas current. A solution of 1.6 g (18.4 mmol) of anhydrousmorpholine (MPL) in anhydrous toluene was slowly added to the abovemixture over 30 minutes. The resultant mixture was stirred at 0° C. forabout 10 minutes until occurrence of foam ceased, whereby an SMEAH-MPLmixed reagent was prepared. 2.03 Grams (6 mmol) of2,3-methylenedithio-6-methoxycarbonyltetrathiafulvalene was dissolved in120 ml of anhydrous toluene, and the resultant mixture was cooled to 0°C. Under an argon gas current, the above-prepared SMEAH-MPL mixedreagent was slowly added dropwise thereto. The resultant mixture wasstirred at 0° C. for 30 minutes, and while the solution had atemperature of 0° C., 2N sulfuric acid was added to acidify thesolution. Anhydrous magnesium sulfate was added to solidify the waterphase of the solution. The resultant mixture solution was filtered, andthe remaining solid was washed with dichloromethane. The former filtrateand the wash liquid were together concentrated and purified by columnchromatography (silica gel/n-hexane:dichloromethane=1:1) to give 0.28 gof a red solid of 6,7-methylenedithio-2-formyltetrathiafulvalene (yield15%).

0.4 Gram (0.62 mmol) of the previously synthesized[2,5-dimethyl-4-(2-tetrathiafulvalenylethenyl)]benzyltriphenylphosphoniumchloride was weighted out, and suspended in 10 ml of THF, and under anargon gas current, 0.8 ml of a hexane solution of n-butyllithium(containing 1.24 mmol of n-butyllithium) was added dropwise to thesuspension. After 5 minutes, 0.19 g (0.62 mmol) of6,7-methylenedithio-2-formyltetrathiafulvalene was added. After 1 hour,50 ml of methanol was added to precipitate a brown solid, followed bywashing with methanol, filtering and drying, whereby 0.2 g of theintended Compound (Ij) was obtained (yield 51%).

Table 1 summarizes the thermal decomposition temperature Td of Compound(Ij), its elemental analysis values, its M/Z in mass spectrometry, itsE₁ and ΔE determined by cyclic voltammetry, and its capability ofdirectly forming a complex. As is clear in Table 1, Compound (Ij) had athermal decomposition temperature of as high as 215° C., or was found tobe excellent in thermal stability.

Further, the elemental analysis values and the M/Z in mass spectrometryshowed that Compound (Ij) was1-[2-(tetrathiafulvalen-2-yl)vinyl]-4-[2-(6,7-methylenedithiotetrathiafulvalen-2-yl)vinyl]-2,5-dimethylbenzeneof the following formula. ##STR16##

Compound (Ij) had E₁ of 0.50 V and ΔE of 0.28 V, or found to be rich inelectron donating nature. As is detailed in Example 22 which will bedescribed later, it was also found that Compound (Ij) was also capableof forming a complex with an electron acceptor under a direct complexforming method.

Example 11 Preparation of1-[2-(tetrathiafulvalen-2-yl)vinyl]-4-[2-(6,7-ethylenedithiotetrathiafulvalen-2-yl)vinyl]-2,5-dimethylbenzene[Compound (Ik)]

2 Grams (3.1 mmol) of[2,5-dimethyl-4-(2-tetrathiafulvalenyletenyl)]benzyltriphenylphosphoniumchloride prepared in the same manner as in Example 10 was suspended in50 ml of THF, and under an argon current, 4 ml of a hexane solution ofn-butyllithium (containing 6.2 mmol of n-butyllithium) was addeddropwise. After 5 minutes, 1 g (3.1 mmol) of2,3-ethylenedithio-6-formyltetrathiafulvalene was added. After 1 hour,200 ml of methanol was added to precipitate a brown solid, followed bywashing with methanol, filtering and drying, whereby 0.9 g of theintended Compound (Ik) was obtained (yield 46%).

Table 1 summarizes the thermal decomposition temperature Td of Compound(Ik), its elemental analysis values, its M/Z in mass spectrometry, itsE₁ and ΔE determined by cyclic voltammetry, and its capability ofdirectly forming a complex. As is clear in Table 1, Compound (Ik) had athermal decomposition temperature of as high as 210° C., or was found tobe excellent in thermal stability.

Further, the elemental analysis values, the M/Z in mass spectrometry and¹ H-NMR shown in FIG. 12 showed that Compound (Ik) was1-[2-(tetrathiafulvalen-2-yl)vinyl]-4-[2-(6,7-ethylenedithiotetrathiafulvalen-2-yl)vinyl]-2,5-dimethylbenzeneof the following formula. ##STR17##

Compound (Ik) had E₁ of 0.52 V and ΔE of 0.30 V, or found to be rich inelectron donating nature. As is detailed in Example 22 which will bedescribed later, it was also found that Compound (Ik) was also capableof forming a complex with an electron acceptor under a direct complexforming method.

Example 12 Preparation of1-[2-(tetrathiafulvalen-2-yl)-vinyl]-4-[2-(tetraselenafulvalen-2-yl)vinyl]-2,5-dimethylbenzene[Compound (Il)]

[2,5-Dimethyl-4-(2-tetrathiafulvalenylethenyl]-benzyltriphenylphosphoniumchloride prepared in the same manner as in Example 10 and2-formyltetraselenafulvalene synthesized in the same manner as inExample 3 were reacted with each other according to a Wittig reaction(n-BuLi/THF system) to give 0.3 g of the intended Compound (Il) yield50%).

Table 1 summarizes the thermal decomposition temperature Td of Compound(Il), its elemental analysis values, its M/Z in mass spectrometry, itsE₁ and ΔE determined by cyclic voltammetry, and its capability ofdirectly forming a complex. As is clear in Table 1, Compound (Il) had athermal decomposition temperature Td of as high as 242° C., or was foundto be excellent in thermal stability.

Further, the elemental analysis values and the M/Z in mass spectrometryshowed that Compound (Il) was1-[2-(tetrathiafulvalen-2-yl)vinyl]-4-[2-(tetraselenafulvalen-2-yl)vinyl]-2,5-dimethylbenzeneof the following formula. ##STR18##

Compound (Il) had E₁ of 0.53 V and ΔE of 0.28 V, or found to be rich inelectron donating nature. As is detailed in Example 22 which will bedescribed later, it was also found that Compound (Il) was also capableof forming a complex with an electron acceptor under a direct complexforming method.

Example 13 Preparation of1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]-2,5-dimethoxybenzene [Compound(Im)]

2,5-Dimethoxy-1,4-bis(chloromethyl)benzene was synthesized according tothe method described in Bull. Chem. Soc. Jpn. 48(2), 497-504.

1.41 Grams (6.0 mmol) of 2,5-dimethoxy-1,4-bis(chloromethyl)benzene and3.78 g (14.4 mmol) of triphenylphosphine were added to 20 ml of DMF, andthe resultant mixture was stirred at 100° C. for 2 hours. After thereaction mixture was allowed to cool, a white powder formed wasseparated by filtering, and washed twice with 5 ml of DMF and 10 ml ofether to give 3.59 g of white crystals of2,5-dimethoxyxylylenebistriphenylphosphonium chloride (yield 80%).

Under an argon atmosphere, 1.6 g (3 mmol) of the2,5-dimethoxyxylylenebistriphenylphosphonium chloride was added to andsuspended in 15 ml of dry THF, 4 ml of a hexane solution of 15%n-butyllithium was added, and the resultant mixture was stirred for 2minutes. Then, a solution of 1.45 g (6.25 mmol) offormyltetrathiafulvalene in 15 ml of THF was added, and the mixture wasstirred for 4 hours. After the reaction, 50 ml of methanol was added toform a precipitate, and the precipitate was separated by filtering,washed with 50 ml of methanol, washed with water, washed with methanoland dried. The solid obtained was recrystallized from DMF to give 0.53 gof a blackish violet powder of the intended Compound (Im) (yield 28.8%).

Table 1 summarizes the thermal decomposition temperature Td of Compound(Im), its elemental analysis values, its M/Z in mass spectrometry, itsE₁ and ΔE determined by cyclic voltammetry, and its capability ofdirectly forming a complex. As is clear in Table 1, Compound (Im) had athermal decomposition temperature of as high as 246° C., or was found tobe excellent in thermal stability.

Further, the elemental analysis values, the M/Z in mass spectrometry and¹ H-NMR shown in FIG. 13 showed that Compound (Im) was1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]-2,5-dimethoxybenzene of thefollowing formula. ##STR19##

Compound (Im) had E₁ of 0.43 V and ΔE of 0.30 V, or found to be rich inelectron donating nature. As is detailed in Example 22 which will bedescribed later, it was also found that Compound (Im) was also capableof forming a complex with an electron acceptor under a direct complexforming method.

Example 14 Preparation of1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]-2,5-dichlorobenzene [Compound(In)]

8.75 Grams (50 mmol) of 2,5-dichloro-1,4-xylene, 20.0 g (112 mmol) ofn-bromosuccinimide and 0.73 g (3 mmol) of benzoyl peroxide weredissolved in 100 ml of carbon tetrachloride, and the resultant mixturewas stirred under heat and refluxed for 6 hours. The reaction liquid waswashed with water and dried over Glauber's salt, and the solvent wasdistilled off to give a white solid. The white solid was recrystallizedfrom ethyl alcohol to give 6.2 g of a white crystal of2,5-dichloro-1,4-bis(bromomethyl)benzene (yield 37.2%).

4 Grams (12 mmol) of the 2,5-dichloro-1,4-bis(bromomethyl)benzene and6.6 g (26.4 mmol) of triphenylphosphine were added to 45 ml of DMF, andthe resultant mixture was stirred at 130° C. for 3 hours. After thereaction mixture was allowed to cool, a white powder formed wasseparated by filtering and washed twice with 10 ml of DMF and 20 ml ofether to give 9.9 g (11.6 mmol) of a white crystal of2,5-dichloroxylylenebistriphenylphosphonium bromide.

Under an argon atmosphere, 2.7 g (3.15 mmol) of the2,5-dichloroxylylenebistriphenylphosphonium bromide was added to andsuspended in 15 ml of dry THF, 4 ml of a hexane solution of 15%n-butyllithium (containing 6.4 mmol of n-butyllithium) was added, andthe resultant mixture was stirred for 2 minutes. Then, a solution of1.45 g (6.25 mmol) of formyltetrathiafulvalene in 15 ml of THF wasadded, and the resultant mixture was stirred for 3 hours. After thereaction, 60 ml of methanol was added to form a precipitate. Theprecipitate was separated by filtering, washed with 30 ml of methanol,washed with water, washed with methanol and dried. The so-obtained solidwas recrystallized from DMF to give 1.16 g of the intended, blackishviolet, Compound (In) (yield 62%).

Table 1 summarizes the thermal decomposition temperature Td of Compound(In), its elemental analysis values, its M/Z in mass spectrometry, itsE₁ and ΔE determined by cyclic voltammetry, and its capability ofdirectly forming a complex. As is clear in Table 1, Compound (In) had athermal decomposition temperature of as high as 260° C., or was found tobe excellent in thermal stability.

Further, the elemental analysis values, the M/Z in mass spectrometry and¹ H-NMR shown in FIG. 14 showed that Compound (In) was1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]-2,5-dichlorobenzene of thefollowing formula. ##STR20##

Compound (In) had E₁ of 0.47 V and ΔE of 0.31 V, or found to be rich inelectron donating nature. As is detailed in Example 22 which will bedescribed later, it was also found that Compound (In) was also capableof forming a complex with an electron acceptor under a direct complexforming method.

Example 15 Preparation of1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]-2,3,5,6-tetramethylbenzene[Compound (Io)]

3.0 Grams (10.1 mmol) of 2,3,5,6-tetramethyl-1,4-bis(bromomethyl)benzeneand 5.3 g (20.2 mmol) of triphenylphosphine were added to 50 ml of DMF,and the resultant mixture was stirred at 120° C. for 1 hour. Thereaction mixture was allowed to cool, a white powder formed wasseparated by filtering, washed with dichloromethane and dried. The yieldof the resultant 2,3,5,6-tetramethylxylylenebistriphenylphosphoniumbromide was 5.35 g (yield 64.6%).

Under an argon atmosphere, 3 g (3.7 mmol) of the2,3,5,6-tetramethylxylylenebistriphenylphosphonium bromide was added toand suspended in 15 ml of dry THF, 6.5 ml of a hexane solution of 15%n-butyllithium was added, and the resultant mixture was stirred for 2minutes. Then, a solution of 1.71 g (7.4 mmol) offormyltetrathiafulvalene in 20 ml of THF was added, and the mixture wasstirred for 1 hour. After the reaction, 50 ml of methanol was added toform a precipitate. The precipitate was separated by filtering, washedwith 50 ml of methanol, washed with water, washed with methanol anddried. The resultant solid was recrystallized from DMF to give 0.4 g ofthe intended, blackish violet, Compound (Io) (yield 18%).

Table 1 summarizes the thermal decomposition temperature Td of Compound(Io), its elemental analysis values, its M/Z in mass spectrometry, itsE₁ and ΔE determined by cyclic voltammetry, and its capability ofdirectly forming a complex. As is clear in Table 1, Compound (Io) had athermal decomposition temperature of as high as 236° C., or was found tobe excellent in thermal stability.

Further, the elemental analysis values and the M/Z in mass spectrometryshowed that Compound (Io) was1,4-bis-[2-(tetrathiafulvalen-2-yl)vinyl]-2,3,5,6-tetramethylbenzene ofthe following formula. ##STR21##

Compound (Io) had E₁ of 0.50 V and ΔE of 0.35 V, or found to be rich inelectron donating nature. As is detailed in Example 22 which will bedescribed later, it was also found that Compound (Io) was also capableof forming a complex with an electron acceptor under a direct complexforming method.

Example 16 Preparation of1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]-2-methylbenzene [Compound (Ip)]

Diethyl 2-methylterephthalonitrile as a starting material was preparedaccording to a known report (Anzalone, Luigi; Hirsch, Jerry A.; J. Org.Chem., 1985, 50, 2128-2133).

Under an argon atmosphere, a 500 ml round-bottomed flask was chargedwith 140 ml of a toluene solution of 4.6 g (33 mmol) of the diethyl2-methylterephthalonitrile, and further, 87 ml of a toluene solution of18.6 g (131 mmol) of diisobutylaluminum hydride was added dropwise at-78° C. The resultant mixture was stirred for 30 minutes as it was, andthen allowed to further react at room temperature for 5 hours. While thereaction mixture was hot, 4 ml of methanol was added to decompose anexcess amount of the diisobutylaluminum hydride. Thereafter, thereaction mixture was poured into 250 ml of a saturated ammonium chlorideaqueous solution, and the resultant mixture was stirred at roomtemperature for 20 minutes. The reaction mixture was recharged into aseparating funnel, 100 ml of 10% sulfuric acid was added, and theresultant mixture was shaken vigorously. And, an organic layer formedwas separated. This organic layer was washed with sodium bicarbonate andsalt water, and dried over magnesium sulfate. The solvent was distilledoff with a rotary evaporator, and the residue was purified by columnchromatography to give 2.8 g (19 mmol) of 2-methylterephthalaldehyde.

A 200 ml round-bottomed flask was charged with 1 g (25 mmol) of lithiumaluminum hydride, and under an argon atmosphere, 50 ml of anhydroustetrahydrofuran was added. While the resultant mixture was stirred, 50ml of an anhydrous tetrahydrofuran solution of 2.8 g (19 mmol) of2-methylterephthalaldehyde was added through a dropping funnel over 20minutes. The resultant mixture was heat-refluxed for 2 hours, and whilethe reaction mixture was hot, 1 ml of water, 1 ml of a 50% sodiumhydroxide aqueous solution and 3 ml of water were consecutively added inthis order. A white precipitate formed was separated by filtering, andthe tetrahydrofuran solution was dried over magnesium sulfate, followedby distilling the solvent off with a rotary evaporator and drying underreduced pressure, whereby 2.7 g (18 mmol) of2,5-bis(hydroxymethyl)toluene was obtained (yield 95%).

A 200 ml round-bottomed flask was charged with the entire amount (2.7 g)of the above 2,5-bis(hydroxymethyl)-toluene, and 60 ml ofdichloromethane was added thereto and suspended therein by stirring themixture. Added dropwise thereto was 4 ml (5.5 mmol) of thionyl chloride,and the resultant mixture was stirred at room temperature for 3 hoursand subjected to extraction by adding 50 ml of water. An organic layerformed was washed with water and with salt water, and the solvent wasdistilled off. The residue was purified by silica gel columnchromatography using 30 g of silica gel to give 2.5 g (13 mmol) of2,5-bis(chloromethyl)-toluene (yield 72%). 2.3 Grams (12 mmol) of this2,5-bis(chloromethyl)toluene and 6.6 g (26.4 mmol) of triphenylphosphinewere added to 45 ml of DMF, and the resultant mixture was stirred underheat at 130° C. for 2 hours. After the reaction mixture was allowed tocool, a white powder formed was separated by filtering, and washed twicewith 10 ml of DMF and 20 ml of ether to give 7.9 g of white crystals of2-methylxylylenebistriphenylphosphonium chloride (yield 95%).

Under an argon atmosphere, 2.1 g (3 mmol) of the above2-methylxylylenebistriphenylphosphonium chloride was added to andsuspended in 15 ml of dry THF, 4 ml of a hexane solution of 5%n-butyllithium was added, and the resultant mixture was stirred for 2minutes. Then, a solution of 1.45 g (6.25 mmol) offormyltetrathiafulvalene in 15 ml of THF was added, and the resultantmixture was stirred for 3 hours. After the reaction, 60 ml of methanolwas added to form a precipitate, the precipitate was separated byfiltering, washed with 30 ml of water, further washed with water, washedwith methanol and dried. The resultant solid was recrystallized from DMFto give 1.1 g of the intended, blackish violet, Compound (Ip) (yield60%).

Table 1 summarizes the thermal decomposition temperature Td of Compound(Ip), its elemental analysis values, its M/Z in mass spectrometry, itsE₁ and ΔE determined by cyclic voltammetry, and its capability ofdirectly forming a complex. As is clear in Table 1, Compound (Ip) had athermal decomposition temperature of as high as 242° C., or was found tobe excellent in thermal stability.

Further, the elemental analysis values and the M/Z in mass spectrometryshowed that Compound (Ip) was1,4-bis-[2-(tetrathiafulvalen-2-yl)vinyl]-2-methylbenzene of thefollowing formula. ##STR22##

Compound (Ip) had E₁ of 0.47 V and ΔE of 0.26 V, or found to be rich inelectron donating nature. As is detailed in Example 22 which will bedescribed later, it was also found that Compound (Ip) was also capableof forming a complex with an electron acceptor under a direct complexforming method.

Example 17 Preparation of1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]-2,5-dihydroxybenzene [Compound(Iq)]

A 100 ml round-bottomed flask was charged with 0.6 g (1 mmol) of1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]-2,5-dimethoxybenzene preparedin the method of Example 13, and the atmosphere inside the flask waschanged to an argon atmosphere. The flask was further charged with 50 mlof anhydrous dimethyl sulfoxide, and the resultant mixture was stirredunder heat in an oil bath at 50° C. to form a solution. With a syringe,0.4 ml (3 mmol) of trimethylsilyl iodide was added dropwise, and theresultant mixture was directly stirred under heat at 50° C. for 24hours. The reaction mixture was cooled, 10 ml of methanol was added, andthe reaction mixture was stirred at room temperature for 24 hours. Thereaction mixture was concentrated by distillation under reducedpressure, 30 ml of methanol was added to form a suspension, and a solidportion was separated by filtering, washed twice with 10 ml of methanol,and recrystallized from N,N-dimethylformamide to give 0.11 g of theintended Compound (Iq) (yield 20%).

Table 1 summarizes the thermal decomposition temperature Td of Compound(Iq), its elemental analysis values, its M/Z in mass spectrometry, itsE₁ and ΔE determined by cyclic voltammetry, and its capability ofdirectly forming a complex. As is clear in Table 1, Compound (Iq) had athermal decomposition temperature of as high as 270° C., or was found tobe excellent in thermal stability.

Further, the elemental analysis values and the M/Z in mass spectrometryshowed that Compound (Iq) was1,4-bis-[2-(tetrathiafulvalen-2-yl)vinyl]-2,5-dihydroxybenzene of thefollowing formula. ##STR23##

Compound (Iq) had E₁ of 0.46 V and ΔE of 0.30 V, or found to be rich inelectron donating nature. As is detailed in Example 22 which will bedescribed later, it was also found that Compound (Iq) was also capableof forming a complex with an electron acceptor under a direct complexforming method.

Example 18 Preparation of1,4-bis[2-(1,4-dithia-5,8-selenafulvalen-2-yl)vinyl]-2,5-dimethylbenzene[Compound (Ir)]

7 Grams (39.8 mmol) of methyl 1,3-dithiol-2-one-4-carboxylate and 6.2 g(48.4 mmol) of triphenylphosphine were refluxed and dissolved in 50 mlof benzene. Added dropwise thereto was 150 ml of a benzene solution of5.8 g (21.1 mmol) of 1,3-diselenol-2-selenone under an argon currentover 1 hour. After the addition, the resultant mixture was refluxed for20 minutes, and the solvent was distilled off, followed by separationand purification by column chromatography, whereby 1.3 g (3.65 mmol) ofmethyl 1,4-dithia-5,8-diselenafulvalen-2-carboxylate was obtained (yield9.2%).

4.9 Grams of a toluene solution of 70% sodiumbis(2-methoxyethoxy)aluminum hydride (SMEAH) (containing 17.1 mmol ofSMEAH) was dissolved in 6 ml of anhydrous toluene, and the resultantmixture was cooled to 0° C. under an argon gas current. A solution of1.6 g (18.4 mmol) of anhydrous morpholin (MPL) in anhydrous toluene wasslowly added dropwise thereto over 30 minutes to prepare an SMEAH-MPLmixed reagent.

1.2 Grams (3.4 mmol) of the methyl1,4-dithia-5,8-diselenafulvalene-2-carboxylate was dissolved in 120 mlof anhydrous toluene, and the resultant mixture was cooled to 0° C. Theabove-prepared SMEAH-MPL mixed reagent was slowly added dropwise underan argon gas current over 30 minutes. After the addition, the mixturewas stirred at 0° C. for 30 minutes, and while the resultant solutionwas at 0° C., 2N sulfuric acid was added to acidify the solution.Anhydrous magnesium sulfate was added to solidify the water phasethereof, the solidified water phase was separated by filtering, and theremaining solid was washed with dichloromethane. These two liquids(filtrate and the dichloromethane wash liquid) were togetherconcentrated, and purified by column chromatography to give 0.5 g (1.5mmol) of 1,4-dithia-5,8-diselena-2-formylfulvalene (yield 45%).

0.55 Gram (0.75 mmol) of 2,5-dimethylxylylenebistriphenylphosphoniumchloride was suspended in 20 ml of anhydrous THF, and at roomtemperature under an argon gas current, 2.0 ml of a hexane solution of15% n-butyllithium (containing 3.2 mmol of n-butyllithium) was added.After the resultant mixture was stirred at room temperature for 5minutes, a solution of 0.5 g (1.5 mmol) of the1,4-dithia-5,8-diselena-2-formylfulvalene in 20 ml of anhydrous THF wasadded, and the mixture was stirred at room temperature for 2 hours. Anequal amount of methanol was added to terminate the reaction, and asolid formed was separated by filtering, washed with methanol, andrecrystallized from DMF to give 280 mg of golden plate-like crystals ofthe intended Compound (Ir) (yield 25%).

Table 1 summarizes the thermal decomposition temperature Td of Compound(Ir), its elemental analysis values, its M/Z in mass spectrometry, itsE₁ and ΔE determined by cyclic voltammetry, and its capability ofdirectly forming a complex. As is clear in Table 1, Compound (Ir) had athermal decomposition temperature of as high as 248° C., or was found tobe excellent in thermal stability.

Further, the elemental analysis values and the M/Z in mass spectrometryshowed that Compound (Ir) was1,4-bis-[2-(1,4-dithia-5,8-diselenafulvalen-2-yl)vinyl]-2,5-dimethylbenzeneof the following formula. ##STR24##

Compound (Ir) had E₁ of 0.53 V and ΔE of 0.22 V, or found to be rich inelectron donating nature. As is detailed in Example 22 which will bedescribed later, it was also found that Compound (Ir) was also capableof forming a complex with an electron acceptor under a direct complexforming method.

Example 19 Preparation of1,4-bis[2-(1,4-diselena-5,8-dithiafulvalen-2-yl)vinyl]-2,5-dimethylbenzene[Compound (Is)]

19 Grams (161 mmol) of 1,3-dithiol-2-one and 31 g (242 mmol) oftriphenylphosphine were refluxed and dissolved in 200 ml of benzene.Added dropwise thereto was a solution of 31 g (81 mmol) of dimethyl1,3-diselenol-2-selenone-4,5-dicarboxylate in 400 ml of benzene under anargon gas current over 3 hours. After the addition, the resultantmixture was refluxed, followed by distillation of the solvent off andseparation and purification by column chromatography, whereby 2.5 g (6.0mmol) of dimethyl 1,4-diselena-5,8-dithia-2,3-dicarboxylate was obtained(yield 7.5%). This compound had a melting point of 115.5° C., and the ¹H-NMR chart thereof is as shown in FIG. 15. 2 Grams (4.8 mmol) of thisdimethyl 1,4-diselena-5,8-dithia-2,3-dicarboxylate was dissolved in 20ml of hexamethylphosphoricamide, 1 g (9.5 mmol) of LiBr.H₂ O was added,and the resultant mixture was stirred for 1 hour. Added thereto was 300ml of water, and the resultant mixture was subjected to extraction withdichloromethane, and an organic phase formed was washed with water,followed by concentration and purification by column chromatography,whereby 0.6 g (1.68 mmol) of methyl1,4-diselena-5,8-dithia-2-carboxylate (melting point 94.0° C.) wasobtained (yield 35%). 0.5 Gram (1.4 mmol) of this product was weighedout and dissolved in 120 ml of anhydrous toluene, and the resultantmixture was cooled to 0° C. The same SMEAH-MPL reagent as that preparedin Example 18 was slowly added dropwise under an argon gas current over30 minutes. After the addition, the resultant mixture was stirred at 0°C. for 30 minutes, and while the resultant solution was at 0° C., 2Nsulfuric acid was added to acidify the solution. Anhydrous magnesiumsulfate was added to solidify the water phase thereof and remove it byfiltering, the remaining solid was washed with dichloromethane, andthese two liquids (filtrate and the dichloromethane wash liquid) weretogether concentrated and purified by column chromatography to give 0.3g (0.9 mmol) of 1,4-diselena-5,8-dithia-2-formylfulvalene.

0.33 Gram (0.45 mmol) of 2,5-dimethylxylylenebistriphenylphosphoniumchloride was suspended in 20 ml of anhydrous THF, and at roomtemperature under an argon gas current, 1.0 ml of a hexane solution of15% n-butyllithium (containing 1.6 mmol of n-butyllithium) was added.The resultant mixture was stirred at room temperature for 5 minutes, asolution of 0.3 g (0.9 mmol) of the1,4-diselena-5,8-dithia-2-formylfulvalene in 10 ml of anhydrous THF wasadded, and the resultant mixture was stirred at room temperature for 2hours. An equal amount of methanol was added to terminate the reaction,and a solid formed was separated by filtering, washed with methanol, andrecrystallized from DMF to give 150 mg of golden plate-like crystals ofthe intended Compound (Is) (yield 25%).

Table 1 summarizes the thermal decomposition temperature Td of Compound(Is), its elemental analysis values, its M/Z in mass spectrometry, itsE₁ and ΔE determined by cyclic voltammetry, and its capability ofdirectly forming a complex. As is clear in Table 1, Compound (Is) had athermal decomposition temperature of as high as 235° C., or was found tobe excellent in thermal stability.

Further, the elemental analysis values and the M/Z in mass spectrometryshowed that Compound (Is) was1,4-bis-[2-(1,4-diselena-5,8-dithiafulvalen-2-yl)vinyl]-2,5-dimethylbenzeneof the following formula. ##STR25##

Compound (Is) had E₁ of 0.52 V and ΔE of 0.23 V, or found to be rich inelectron donating nature. As is detailed in Example 22 which will bedescribed later, it was also found that Compound (Is) was also capableof forming a complex with an electron acceptor under a direct complexforming method.

Example 20 Preparation of1,4-bis[2-(tetraselenafulvalen-2-yl)vinyl]-2,5-dichlorobenzene [Compound(It)]

Under an argon atmosphere, 2.7 g (3.2 mmol) of2,5-dichloroxylylenebistriphenylphosphonium bromide was added to andsuspended in 15 ml of dry THF, 4 ml of a hexane solution of 15%n-butyllithium was added, and the resultant mixture was stirred for 2minutes. Then, a solution of 2.6 g (6.25 mmol) offormyltetraselenafulvalene in 15 ml of THF was added, and the mixturewas stirred for 3 hours. After the reaction, 60 ml of methanol was addedto form a precipitate. The precipitate was separated by filtering,followed by washing with 30 ml of methanol, washing with water, washingwith methanol and drying. The resultant product was recrystallized fromDMF to give 1.6 g of the intended, blackish violet, Compound (It) (yield25%).

Table 1 summarizes the thermal decomposition temperature Td of Compound(It), its elemental analysis values, its M/Z in mass spectrometry, itsE₁ and ΔE determined by cyclic voltammetry, and its capability ofdirectly forming a complex. As is clear in Table 1, Compound (It) had athermal decomposition temperature of as high as 245° C., or was found tobe excellent in thermal stability.

Further, the elemental analysis values and the M/Z in mass spectrometryshowed that Compound (It) was1,4-bis-[2-(tetraselenafulvalen-2-yl)vinyl]-2,5-dichlorobenzene of thefollowing formula. ##STR26##

Compound (It) had E₁ of 0.50 V and ΔE of 0.20 V, or found to be rich inelectron donating nature. As is detailed in Example 22 which will bedescribed later, it was also found that Compound (It) was also capableof forming a complex with an electron acceptor under a direct complexforming method.

Example 21 Preparation of1,4-bis[4,5,8-trithia-1-selenafulvalen-2-yl)vinyl]-2,5-dimethylbenzene[Compound I(u)]

2.8 Grams (20.8 mmol) of 1,3-dithiol-2-thione and 8 g (30.5 mmol) oftriphenylphosphine were dissolved in 30 ml of benzene and the resultantmixture was refluxed. A solution of 4 g (10.2 mmol) of dimethyl1,3-diselenol-2-selenone-4,5-dicarboxylate in 200 ml of benzene wasslowly added dropwise thereto under an argon gas current over 2 hours.After the addition, the resultant mixture was further refluxed for 30minutes, and the solvent was distilled off, followed by purification bycolumn chromatography, whereby 1.6 g (4.36 mmol) of grayish browndimethyl 4,5,8-trithia-1-selenafulvalene-2,3-dicarboxylate (meltingpoint 114.1° C.) was obtained (yield 43%). The total amount of thisproduct was dissolved in 8 ml of HMPA, 0.9 g (8.6 mmol) of LiBr.H₂ O wasadded, and the resultant mixture was stirred at 80° C. for 1 hour. Addedthereto was 100 ml of water, the resultant mixture was subjected toextraction with dichloromethane, and an organic layer formed was washedwith water, concentrated and purified by column chromatography to give1.2 g (3.9 mmol) of a orange solid (melting point 112.9° C.) of methyl4,5,8-trithia-1-selenafulvalene-2-carboxylate (yield 89%).

4.1 Milliliters of a toluene solution containing 14 mmol of sodiumbis(2-methoxyethoxy)aluminum hydride (SMEAH) was dissolved in 4 ml ofanhydrous toluene, and the resultant mixture was cooled to 0° C. Addeddropwise thereto was 4 ml of a toluene solution of 1.3 g (14.9 mmol) ofanhydrous morpholine (MPL) under an argon gas current over 10 minutes toprepare an SMEAH-MPL mixed reagent. 1.7 Grams (5.5 mmol) of the methyl4,5,8-trithia-1-selenafulvalene-2-carboxylate was dissolved in 40 ml ofanhydrous toluene, and the resultant mixture was cooled to -10° C. Theabove-prepared SMEAH-MPL mixed reagent was slowly added dropwise theretounder an argon gas current over 30 minutes. After the addition, theresultant solution was stirred for 30 minutes, 2N sulfuric acid wasadded to convert the solution to weakly acidic, and then, sodium sulfatewas added to solidify the aqueous phase thereof. The remaining organiclayer was recovered by filtering, and the sodium sulfate was washed withdichloromethane. The organic phases obtained were together concentratedand purified by column chromatography to give 0.27 g (0.825 mmol) of4,5,8-trithia-1-selena-2-formylfulvalene (yield 15%). This compound hada melting point of 116.8° C. and a decomposition temperature of 189° C.,and the ¹ H-NMR chart thereof is as shown in FIG. 16.

0.28 Gram (0.39 mmol) of 2,5-dimethylxylylenebistriphenylphosphoniumchloride was suspended in 20 ml of anhydrous THF, and at roomtemperature under an argon gas current, 0.5 ml of a hexane solution of5% n-butyllithium (containing 0.8 mmol of n-butyllithium) was added. Thecolor of the resultant solution was changed from white to reddish brown,which showed ylide formation. After the solution was stirred at roomtemperature for 10 minutes, a solution of 0.25 g (0.8 mmol) of the4,5,8-trithia-1-selena-2-formylfulvalene in 20 ml of THF was added, andthe resultant mixture was stirred at room temperature for 2 hours. Anequal amount of methanol was added to terminate the reaction, and asolid formed was separated by filtering, followed by washing withmethanol and recrystallization from DMF, whereby 70 mg of brownplate-like crystals of the intended Compound (Iu) was obtained (yield27%).

Table 1 summarizes the thermal decomposition temperature Td of Compound(Iu), its elemental analysis values, its M/Z in mass spectrometry, itsE₁ and ΔE determined by cyclic voltammetry, and its capability ofdirectly forming a complex. As is clear in Table 1, Compound (Iu) had athermal decomposition temperature of as high as 235° C., or was found tobe excellent in thermal stability.

Further, the elemental analysis values, the M/Z in mass spectrometry andthe ¹ H-NMR results shown in FIG. 17 showed that Compound (Iu) was1,4-bis-[2-(4,5,8-trithia-1-selenafulvalen-2-yl)vinyl]-2,5-dimethylbenzeneof the following formula. ##STR27##

Compound (Iu) had E₁ of 0.53 V and ΔE of 0.20 V, or found to be rich inelectron donating nature. As is detailed in Example 22 which will bedescribed later, it was also found that Compound (Iu) was also capableof forming a complex with an electron acceptor under a direct complexforming method.

Comparative Example 1

The following three known electron-donating compounds (a), (b), and (c)were measured for a melting point, E₁ and ΔE, and examined with regardto the capability of directly forming a complex.

(a) Bisethylenedithiotetrathiafulvalene (BEDTTTF) ##STR28## (b)Tetramethyltetrathiafulvalene (TMTTF) ##STR29## (c) Tetrathiafulvalene(TTF) ##STR30##

Table 1 shows the results of the above measurements. Table 1 shows thatthe known compounds (a) BEDTTTF and (b) TMTTF are inferior in electrondonating nature since these compounds had E₁ of as high as 1.0 V and0.86 V and ΔE of as great as 0.44 and 0.53 respectively. As is shown inComparative Examples 2 and 3 to be described later, therefore, thesecompounds were incapable of directly forming a complex. It was alsoshown that the known compound (c) TTF was inferior in electron donatingnature since it had E₁ of as high as 0.85 V and ΔE of as great as 0.41V, and that it was poor in thermal stability since it had a meltingpoint of as low as 115° to 119° C.

                                      TABLE 1                                     __________________________________________________________________________    Compound   Thermal                                                            of general decomposition                                                      formula    temperature   Elemental analysis value                             No. (I)    Td (°C.)                                                                             C  H O S  Se Cl                                      __________________________________________________________________________    Ex. 1                                                                             Compound                                                                             225     Calculated                                                                          49.4                                                                             2.6 47.9                                              (Ia)           Found 49.5                                                                             2.7 47.8                                          Ex. 2                                                                             Compound                                                                             270     Calculated                                                                          51.2                                                                             3.2 45.5                                              (Ib)           Found 51.4                                                                             3.3 45.3                                          Ex. 3                                                                             Compound                                                                             230     Calculated                                                                          30.7                                                                             1.9    67.4                                           (Ic)           Found 30.6                                                                             2.0    67.0                                       Ex. 4                                                                             Compound                                                                             245     Calculated                                                                          33.8                                                                             2.6    63.6                                           (Id)           Found 34.0                                                                             2.7    63.2                                       Ex. 5                                                                             Compound                                                                             227     Calculated                                                                          45.3                                                                             3.0 51.8                                              (Ie)           Found 45.2                                                                             3.2 51.4                                          Ex. 6                                                                             Compound                                                                             236     Calculated                                                                          45.0                                                                             3.5 51.5                                              (If)           Found 45.0                                                                             3.6 51.4                                          Ex. 7                                                                             Compound                                                                             220     Calculated                                                                          48.9                                                                             2.8                                                                             2.8                                                                             45.8                                              (Ig)           Found 49.1                                                                             3.0                                                                             3.1                                                                             44.8                                          Ex. 8                                                                             Compound                                                                             248     Calculated                                                                          46.4                                                                             2.4 45.0  6.2                                         (Ih)           Found 46.5                                                                             2.3 44.8  6.2                                     Ex. 9                                                                             Compound                                                                             270     Calculated                                                                          54.4                                                                             4.2 41.4                                              (Ii)           Found 54.5                                                                             4.2 41.3                                          Ex. 10                                                                            Compound                                                                             215     Calculated                                                                          47.0                                                                             2.8 50.1                                              (Ij)           Found 46.9                                                                             2.9 49.8                                          Ex. 11                                                                            Compound                                                                             210     Calculated                                                                          47.9                                                                             3.1 49.1                                              (Ik)           Found 48.0                                                                             3.1 49.0                                          Ex. 12                                                                            Compound                                                                             242     Calculated                                                                          38.4                                                                             2.4 17.1                                                                             42.1                                           (Il)           Found 38.6                                                                             2.4 16.9                                                                             42.0                                       Ex. 13                                                                            Compound                                                                             246     Calculated                                                                          48.5                                                                             3.0                                                                             5.4                                                                             43.1                                              (Im)           Found 48.4                                                                             3.0                                                                             5.3                                                                             43.3                                          Ex. 14                                                                            Compound                                                                             260     Calculated                                                                          43.8                                                                             2.0 42.4  11.8                                        (In)           Found 43.6                                                                             2.1 42.0  12.3                                    Ex. 15                                                                            Compound                                                                             236     Calculated                                                                          52.0                                                                             5.3 42.7                                              (Io)           Found 51.9                                                                             5.3 42.8                                          Ex. 16                                                                            Compound                                                                             242     Calculated                                                                          50.4                                                                             2.9 46.7                                              (Ip)           Found 50.8                                                                             2.9 46.3                                          Ex. 17                                                                            Compound                                                                             270     Calculated                                                                          46.6                                                                             2.5                                                                             5.7                                                                             45.2                                              (Iq)           Found 46.8                                                                             2.5                                                                             5.9                                                                             44.8                                          Ex. 18                                                                            Compound                                                                             248     Calculated                                                                          38.4                                                                             2.4 17.1                                                                             42.1                                           (Ir)           Found 38.6                                                                             2.4 16.9                                                                             42.1                                       Ex. 19                                                                            Compound                                                                             232     Calculated                                                                          38.4                                                                             2.4 17.1                                                                             42.1                                           (Is)           Found 38.7                                                                             2.3 17.2                                                                             41.8                                       Ex. 20                                                                            Compound                                                                             245     Calculated                                                                          27.0                                                                             1.2    64.6                                                                             7.2                                         (It)           Found 27.2                                                                             1.2    64.0                                                                             7.6                                     Ex. 21                                                                            Compound                                                                             235     Calculated                                                                          43.1                                                                             2.7 29.3                                                                             24.1                                           (Iu)           Found 42.8                                                                             2.6 29.8                                                                             24.8                                       Comp.                                                                             Known  mp.     not measured                                               Ex. 1                                                                             compound (a)                                                                         246                                                                    BEDTTTF                                                                              -247                                                                   Known  mp.     not measured                                                   compound (b)                                                                         244                                                                    TMTTF  -245                                                                   Known  mp.     not measured                                                   compound (c)                                                                         115                                                                    TTF    -119                                                               __________________________________________________________________________        Compound                   Capability of                                      of general                 directly forming                               No. formula (I)                                                                              M/Z  E1 (V)                                                                              ΔE (V)                                                                       complex                                        __________________________________________________________________________    Ex. 1                                                                             Compound (Ia)                                                                            534  0.49  0.31 possible (O)                                   Ex. 2                                                                             Compound (Ib)                                                                            562  0.47  0.23 O                                              Ex. 3                                                                             Compound (Ic)                                                                            937  0.57  0.20 O                                              Ex. 4                                                                             Compound (Id)                                                                            993  0.53  0.30 O                                              Ex. 5                                                                             Compound (Ie)                                                                            742  0.55  0.26 O                                              Ex. 6                                                                             Compound (If)                                                                            746  0.52  0.32 O                                              Ex. 7                                                                             Compound (Ig)                                                                            564  0.46  0.31 O                                              Ex. 8                                                                             Compound (Ih)                                                                              568.5                                                                            0.49  0.31 O                                              Ex. 9                                                                             Compound (Ii)                                                                            618  0.48  0.32 O                                              Ex. 10                                                                            Compound (Ij)                                                                            638  0.50  0.28 O                                              Ex. 11                                                                            Compound (Ik)                                                                            652  0.52  0.30 O                                              Ex. 12                                                                            Compound (Il)                                                                            750  0.53  0.28 O                                              Ex. 13                                                                            Compound (Im)                                                                            594  0.43  0.30 O                                              Ex. 14                                                                            Compound (In)                                                                            603  0.47  0.31 O                                              Ex. 15                                                                            Compound (Io)                                                                            600  0.50  0.35 O                                              Ex. 16                                                                            Compound (Ip)                                                                            548  0.47  0.26 O                                              Ex. 17                                                                            Compound (Iq)                                                                            566  0.46  0.30 O                                              Ex. 18                                                                            Compound (Ir)                                                                            750  0.53  0.22 O                                              Ex. 19                                                                            Compound (Is)                                                                            750  0.52  0.23 O                                              Ex. 20                                                                            Compound (It)                                                                            979  0.50  0.20 O                                              Ex. 21                                                                            Compound (Iu)                                                                            656  0.53  0.20 O                                              Comp.                                                                             Known      not  1.0   0.44 impossible (x)                                 Ex. 1                                                                             compound (a)                                                                             measured                                                           BEDTTTF                                                                       Known      not  0.86  0.53 X                                                  compound (b)                                                                             measured                                                           TMTTF                                                                         Known      not  0.85  0.41 O                                                  compound (c)                                                                             measured                                                           TTF                                                                       __________________________________________________________________________

Preparation Example of complex Example 22

After a flask was charged with 30 mg of the1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]benzene [Compound (Ia)] obtainedin Example 1, 100 ml of chlorobenzene was added, and the resultantmixture was heated to 120° C. to form a solution. The solution was mixedwith 500 mg of tetra-n-butylammonium triiodide, and the resultantmixture was stirred for 5 minutes. The reaction product obtained wasrecovered by filtering, washed with dichloromethane and dried to give acomplex consisting of Compound (Ia) as an electron donor and I₃ as anelectron acceptor.

Complexes each consisting one of Compounds (Ib) to (Iu) as an electrondonor and I₃ as an electron acceptor were prepared in the same manner asabove.

As described above it has been found that complexes can be obtained byonly mixing Compounds (Ia) to (Iu) obtained in Examples 1 to 21 with anelectron acceptor.

These twenty-one complexes were (1) measured for identification, (2)subjected to elemental analysis with regard to an electron acceptor, (3)measured for an electron donor/electron acceptor molar ratio (D/A) and(4) measured for electrical conductivity.

In addition, the above measurements (1), (3) and (4) were carried out inthe following manner.

(1) Identification of complex

The identification of complexes was conducted by examining the degree ofelectrical conductivity and identifying an electron acceptor by means ofICP (inductive coupling plasma emission spectral analyzer), an X-raymicroanalyzer or voltammetry.

(3) Measurement of D/A

Complexes were aggregates of microcrystallites, and D/A as an averagewas determined on the basis of the following equation. ##EQU1##

in which:

d: molecular weight of electron donor

a: molecular weight of electron acceptor

w: weight ratio of atom measured (%), and

r: atomic ratio measured in electron acceptor.

(4) Measurement of electrical conductivity

In the case of acicular crystals, lead wires were connected to a complexwith a gold paste, and the complex was measured according to aconventional four point probe method. In the case of a powder sample,the powder was charged into a glass cell having a diameter of 1 mm andpressure-molded at a cylinder pressure of about 130 kg/cm² to form acolumn having a length of about 1 to 3 mm and a diameter of 1 mm, andthe column was used as a sample for the measurement. Electrodes wereattached to the sample with a gold paste, and the sample was measuredfor electrical conductivity according to a four point probe method.

Table 2 summarizes the results of these measurements. Table 2 shows thateach complex consisting of one of Compounds (Ia) to (Iu) obtained inExamples 1 to 21 as an electron donor and I₃ as an electron acceptor haselectrical conductivity. In particular, the complex consisting ofCompound (Ic) obtained in Example 3 as an electron donor and I₃ as anelectron acceptor and the complex consisting of Compound (Ir) obtainedin Example 18 as an electron donor and I₃ as an electron acceptorexhibited electrical conductivity of as high as 200 S/cm.

Example 23

A flask was charged with 50 mg of1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]-2,5-dimethylbenzene [Compound(Ib)] obtained in Example 2, and 500 mg of iodine was added. Theresultant mixture was allowed to stand at room temperature for 3 days.Then, the reaction mixture was taken out, washed and dried to give acomplex. Table 2 shows the results of analysis of the complex obtainedby this direct complex-forming method. Table 2 shows that this complexhad electrical conductivity.

Example 24

After a flask was charged with 30 mg of1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]benzene [Compound (Ia)] obtainedin Example 1, 100 mg of xylene was added, and the resultant mixture washeated to 120° C. to form a solution. The solution was mixed with 500 mgof tetra-n-butylammonium trichloride, and the mixture was stirred for 5minutes. The reaction product was filtered, washed with dichloromethane,and dried to give a complex. Table 2 shows the results of analysis ofthe complex obtained by this direct complex-forming method. Table 2shows that this complex had electrical conductivity.

Example 25

A flask was charged with 30 mg of1,4-bis[2-(tetrathiafulvalen-2-yl)vinyl]-2,5-dimethylbenzene [Compound(Ib)] obtained in Example 2, and 100 mg of xylene was added. Theresultant mixture was heated to 120° C. to form a solution. The solutionwas mixed with 500 mg of tetra-n-butylammonium trichloride, and themixture was stirred for 5 minutes. The reaction product was filtered,washed with dichloromethane, and dried to give a complex. Table 2 showsthe results of analysis of the complex obtained by this directcomplex-forming method. Table 2 shows that this complex had electricalconductivity.

Example 26

A flask was charged with 30 mg of1,4-bis[2-(6,7-ethylenedithiotetrathiafulvalen-2-yl)vinyl]-2,5-dimethylbenzene[Compound (Ie)] obtained in Example 5, and 100 ml of chlorobenzene wasadded. The resultant mixture was heated to 120° C. to form a solution.The solution was mixed with 200 mg of tetra-n-butylammoniumbromodiiodide, and the mixture was stirred for 5 minutes. The reactionmixture was slowly cooled to room temperature, and the reaction productwas recovered by filtering, washed with dichloromethane, and dried togive a complex. Table 2 shows the results of analysis of the complexobtained by this direct complex-forming method. Table 2 shows that thiscomplex had electrical conductivity.

Comparative Example 2

A flask was charged with 15 mg of bisethylenedithiotetrathiafulvalene(BEDTTTF), and another flask was charged with 15 mg oftetramethyltetrathiafulvalene (TMTTF). Then, 100 mg of chlorobenzene wascharged to each of the flasks, and the resultant mixtures were heated to120° C. to form solutions. Each of the solutions was mixed with 300 mgof tetra-n-butylammonium trichloride, and the resultant mixtures werestirred for 5 minutes. It has been found that none of the BEDTTTF andTMTTF do not form any complex under a direct complex-forming method.

Comparative Example 3

A flask was charged with 15 mg of tetrathiafulvalene (TTF), and 100 mgof chlorobenzene was added. Then the resultant mixture was heated to120° C. to form a solution. The solution was mixed with 300 mg oftetra-n-butylammonium trichloride, and the resultant mixture was stirredfor 5 minutes to form a complex. The electrical conductivity of thecomplex was 50 S/cm. The results of X-ray diffractometry thereof showedthat the electron donor was converted to I instead of I₃, and it isconsidered that the complex was formed in a different process from thoseof the above Examples.

                                      TABLE 2                                     __________________________________________________________________________           Example                                                                Example                                                                              No. for                                                                No. for                                                                              prepa-            Elemental                                            prepa- ration            analysis                                             ration of   Electron                                                                              Electron                                                                           of electron Electrical                               of     electron                                                                           donor   acceptor                                                                           donor (wt %)                                                                              conductivity                             complex                                                                              donor                                                                              (D)     (A)  I  Cl Br D/A                                                                              (S/cm)                                   __________________________________________________________________________    22      1   Compound (Ia)                                                                         I.sub.3                                                                            35.4     1.3                                                                              20                                       22      2   Compound (Ib)                                                                         I.sub.3                                                                            38.1     1.1                                                                              50                                       22      3   Compound (Ic)                                                                         I.sub.3                                                                            27.0     1.1                                                                              200                                      22      4   Compound (Id)                                                                         I.sub.3                                                                            20.4     1.5                                                                              30                                       22      5   Compound (Ie)                                                                         I.sub.3                                                                            26.8     1.4                                                                              10                                       22      8   Compound (If)                                                                         I.sub.3                                                                            24.2     1.6                                                                               5                                       22      7   Compound (Ig)                                                                         I.sub.3                                                                            36.0     1.2                                                                                0.5                                    22      8   Compound (Ih)                                                                         I.sub.3                                                                            34.0     1.3                                                                                0.8                                    22      9   Compound (Ii)                                                                         I.sub.3                                                                            33.9     1.2                                                                              20                                       22     10   Compound (Ij)                                                                         I.sub.3                                                                            29.9     1.4                                                                                1.5                                    __________________________________________________________________________    Example                                                                              Example                                                                No. for                                                                              No. for           Elemental                                            prepa- prepa-            analysis                                             ration ration                                                                             Electron                                                                              Electron                                                                           of electron Electrical                               of     of   donor   acceptor                                                                           donor (wt %)                                                                              conductivity                             complex                                                                              electron                                                                           (D)     (A)  I  Cl Br D/A                                                                              (S/cm)                                   __________________________________________________________________________    22     11   Compound (Ik)                                                                         I.sub.3                                                                            32.7     1.2                                                                               3                                       22     12   Compound (Il)                                                                         I.sub.3                                                                            28.1     1.3                                                                              40                                       22     13   Compound (Im)                                                                         I.sub.3                                                                            36.8     1.1                                                                              20                                       22     14   Compound (In)                                                                         I.sub.3                                                                            38.7     1.0                                                                              50                                       22     15   Compound (Io)                                                                         I.sub.3                                                                            31.2     1.4                                                                                0.2                                    22     16   Compound (Ip)                                                                         I.sub.3                                                                            38.7     1.1                                                                              60                                       22     17   Compound (Iq)                                                                         I.sub.3                                                                            34.1     1.3                                                                              20                                       22     18   Compound (Ir)                                                                         I.sub.3                                                                            31.6     1.1                                                                              200                                      22     19   Compound (Is)                                                                         I.sub.3                                                                            33.7     1.0                                                                              180                                      22     20   Compound (It)                                                                         I.sub.3                                                                            27.0      1.05                                                                            200                                      22     21   Compound (Iu)                                                                         I.sub.3                                                                            34.6     1.1                                                                              80                                       23      2   Compound (Ib)                                                                         I     8.0      2.6*                                                                                0.02                                 24      1   Compound (Ia)                                                                         Cl.sub.3                                                                              14.3  1.2                                                                                1.2                                    25      2   Compound (Ib)                                                                         Br.sub.3   24.7                                                                             1.3                                                                                0.2                                    26      5   Compound (Ie)                                                                         I.sub.2 Br                                                                         20.7   6.5                                                                             1.2                                                                              10                                       Comparative                                                                          --   BEDTTTF         no complex formed by direct                       Example 2                                                                            --   TMTTF           complex-forming method                            Comparative                                                                          --   TTF     I    30.4      1.4*                                                                            50                                       Example 3                                                                     __________________________________________________________________________     *Calculated by taking anion as I.                                        

In crystals having a relatively large size, D/A was determined bymeasuring the amounts of sulfur (S) and iodine (I) with an X-raymicroanalyzer. The data obtained showed that complexes were formed ofcrystals in various ratios. Table 3 shows the data.

                                      TABLE 3                                     __________________________________________________________________________          Example                                                                 Example                                                                             No. for                                                                 No. for                                                                             Prepa-          Peak height                                             prepa-                                                                              ration          ratio in                                                ration                                                                              of   Electron                                                                            Electron                                                                           X-ray micro-                                                                           *1                                             of    electron                                                                           donor acceptor                                                                           analyzer Corrected                                      complex                                                                             donor                                                                              (D)   (A)  S:I      S:I   D/A                                      __________________________________________________________________________    22    2    Compound                                                                            I.sub.3                                                                            Acicular                                                                           10:4.3                                                                             8:3.1                                                                              0.97                                                (Ib)       Column                                                                             10:2.9                                                                             8:2.1                                                                              1.43                                     22    5    Compound                                                                            I.sub.3                                                                            Acicular                                                                           10:2.0                                                                            12:2.2                                                                              1.36                                                (Ie)       Column                                                                             10:1.3                                                                            12:1.4                                                                              2.14                                     26    5    Compound                                                                            I.sub.2 Br                                                                         Acicular                                                                           10:2.1                                                                            12:2.3                                                                              0.87                                                (Ie)       Column                                                                             10:1.0                                                                            12:1.1                                                                              1.82                                     __________________________________________________________________________     *1 Corrected on the basis of S and I intensities of BEDTTTF as a referenc     sample, measured by Xray microanalyzer.                                  

As specified above, according to this invention, there is provided anovel organic compound having excellent electron donating nature, beingcapable of forming a complex with an electron acceptor and beingexcellent in thermal stability.

Further, there is also provided an electrically conductive complexcontaining this novel organic compound as an electron donor.

What is claimed is:
 1. A thia- and/or selenafulvalenyl group-containingcompound of the formula (I), ##STR31## wherein: each of X₁, X₂, X₃, X₄,X'₁, X'₂, X'₃ and X'₄ is independently S or Se,Y is an electron donatinggroup selected from the group consisting of a lower alkyl group having 1to 5 carbon atoms, a lower alkoxy group having 1 to 5 carbon atoms, athio lower alkoxy group having 1 to 5 carbon atoms, an amino group and ahydroxyl group or an electron accepting group selected from the groupconsisting of a halogen atom, a cyano group and a nitro group, said Yhaving a size which is not so large as to prevent molecular overlapping,m is an integer of 0 to 4, each of Z₁, Z₂, Z'₁ and Z'₂ is independentlya hydrogen atom, C_(n) H_(2n+1) in which n is an integer of 1 to 5, orXC_(n) H_(2n+1) in which X is S or Se and n is an integer of 1 to 5, oralternatively, a combination of Z₁ with Z₂ and that of Z'₁ with Z'₂ areC_(n) H_(2n) in which n is an integer of 1 to 5, or X(C_(n) H_(2n))_(n')X in which X is S or Se and n' is an integer of 1 to 3, and each of R₁,R₂, R₃, R'₁, R'₂ and R'₃ is independently a hydrogen atom or C_(n)H_(2n+1) in which n is an integer of 1 to
 5. 2. The thia- and/orselenafulvalenyl group-containing compound according to claim 1, whereina group of the formula (II) ##STR32## which is positioned in one end ofthe formula (I) is one member selected from the following groups 1 to 8:##STR33##
 3. The thia- and/or selenafulvalenyl group-containing compoundaccording to claim 1, wherein a group of the formula (III) ##STR34##which is positioned in one end of the formula (I) is one member selectedfrom the following groups 1 to 8: ##STR35##
 4. The thia- and/orselenafulvalenyl group-containing compound according to claim 1, whereina lower alkyl group of C_(n) H_(2n+1) in which n is an integer of 1 to5, defined as Z₁, Z₂, Z'₁ and Z'₂, is one member selected from the groupconsisting of methyl, ethyl, n-propyl, iso-propyl, n-butyl andtert-butyl groups.
 5. The thia- and/or selenafulvalenyl group-containingcompound according to claim 1, wherein a thio or seleno lower alkoxygroup of XC_(n) H_(2n+1) in which X is S or Se and n is an integer of 1to 5, defined as Z₁, Z₂, Z'₁ and Z'₂, is one member selected from thegroup consisting of thiomethoxy, selenomethoxy, thioethoxy,selenoethoxy, thio-n-propoxy, seleno-n-propoxy, thio-iso-propoxy,seleno-iso-propoxy, thio-n-butoxy, seleno-n-butoxy, thio-iso-butoxy,seleno-iso-butoxy, thio-tert-butoxy and seleno-tert-butoxy groups. 6.The thia- and/or selenafulvalenyl group-containing compound according toclaim 1, wherein a lower alkylene group of C_(n) H_(2n) in which n is aninteger of 1 to 5, constituted of a combination of Z₁ with Z₂ or that ofZ'₁ with Z'₂ is one member selected from the group consisting ofmethylene, ethylene, propylene and butylene groups.
 7. The thia- and/orselenafulvalenyl group-containing compound according to claim 1, whereina terminal sulfur or selenium atom-containing alkylene group ofX(CH₂)_(n') X in which X is S or Se and n' is an integer of 1 to 3,constituted of a combination of Z₁ with Z₂ or that of Z'₁ with Z'₂ is aone member selected from the group consisting of S--CH₂ --S, Se--CH₂--Se, S--(CH₂)₂ --S and Se--(CH₂)₂ --Se.
 8. The thia- and/orselenafulvalenyl group-containing compound according to claim 1, whereina lower alkyl group of C_(n) H_(2n+1) in which n is an integer of 1 to 5defined as R₁, R₂, R₃, R'₁, R'₂ and R'₃, is one member selected from thegroup consisting of methyl, ethyl, n-propyl, iso-propyl, n-butyl,iso-butyl and tert-butyl groups.